->''"Heat level critical. Shutdown imminent."''
-->-- '''On-board computer''', ''VideoGame/MechWarrior 2''

Some games give you unlimited ammo, but the designer doesn't want you to fire continuously, so your gun will overheat if you fire continuously for too long, and you have to wait for it to cool down before you can use it again. Alternately, you may have to reload, but have unlimited magazines, which is functionally identical. This doesn't just apply to guns. For example, in Excitebike, the motorcycle will overheat if you go fast for too long.

A particularly bizarre version can occur in games that feature mounted and handheld versions of the same machine gun, which may be governed by totally separate rules; for example, one may require reloading while the other does not but is able to overheat. Real mounted weapons often have rather obvious and bulky extra cooling hardware installed, though this is rarely reflected in-game.

This can be partly considered an example of TruthInTelevision, as the dissipation of waste heat from various forms of technology is a major design consideration that is often overlooked; however, in video games the effect is typically exaggerated by a variable margin in terms of speed and grossly under-exaggerated in terms of severity; overheating a machine gun will typically cause it to steam as if it has a water jacket, without the risk of rounds spontaneously igniting (known as "cooking off") or permanent barrel damage that come with overheating a real gun. May be partially justified by having the overheat meter represent a safety threshold imposed by an automated weapon control system or the shooter himself, and not the absolute maximum temperature at which the weapon is capable of firing. However, keeping firing at the risk of weapon damage is generally not an option. Typically, the quick-change barrels of modern machine guns are not represented either, and there is no way to deal with an overheated barrel but wait for it to cool back down (which, for gameplay reasons, happens surprisingly fast).

Gatling Guns, especially of the modern Minigun variety, often fall victim to this trope, despite the fact that their multiple rotating barrels is a special design meant to avoid overheating.

Essentially an inverted ChargeMeter, and similar in function to a SprintMeter, though the latter will generally go down instead of up. Contrast PentUpPowerPeril when danger comes from the lack of use rather than overuse.

If the weapons are in space, it's an aversion of SpaceIsCold.

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!!Examples:

[[foldercontrol]]

[[folder: Literature ]]

* One ''DearAmerica'' book set during the VietnamWar had a US Marine stationed near Khe Sanh as the viewpoint character. Twice in the book, the next Marine company over came under heavy attack and returned fire with mortars. Then the mortars began to overheat, and the main character's company resorted to peeing on them to cool them down.

[[/folder]]

[[folder: Tabletop RPG ]]

* ''{{Traveller}}'' Classic. In Book 4 ''Mercenary'', several rapid firing weapons (such as machine guns) would overheat and jam if you fired them too often, requiring repair.
* In ''{{Battletech}}'', heat is an important balancing factor. [=BattleMechs=] are environmentally sealed, powered by fusion engines and artificial muscles that aren't exactly 100% efficient, and often bristling with energy, ballistic, and/or missile weapons; virtually everything they do starting with simple movement will cause heat to build up, which needs to be funneled out of the 'Mech via dedicated 'heat sinks'. Build up heat faster than those can handle, and your 'Mech will slow down and the accuracy of its weapons fire will suffer until they have caught up again. At sufficiently high levels it may even automatically shut down and/or see explosive ammo start to cook off.
** There's also the in-universe anecdote (from the original ''Technical Readout 3025'', may or may not have made it into later books) about the overenthusiastic all-''Enforcer'' lance commander who supposedly exhorted his troops to fire "until your [auto]cannon glows. If need be, until it explodes!". No points for guessing what according to that story happened to ''him'' in just that battle...
* Many, many R&D megaweapons in ''TabletopGame/{{Paranoia}}''. They also tend to explode regularly.
* Some weapons in ''TabletopGame/{{Warhammer 40000}}'' have a special rule called "Gets Hot!"; each time they're fired they have a 1 in 6 chance of "overheating" and injuring the operator. Most weapons with this rule are handheld plasma weapons, which harness energy equivalent to that of a star with technology [[VestigialEmpire the engineers have lost the blueprints to]].
** They're [[http://www.dakkadakka.com/s/i/at/2008/3/Plasma-23124627.jpg totally worth it]], [[MemeticMutation though]].
* {{GURPS}} High Tech [[TheDevTeamThinksOfEverything naturally]] has detailed rules for overheating of automatic weapons, including barrel swaps, heating management by burst firing, and the possibility of spectacular malfunctions. GURPS Ultra Tech has optional overheating rules for energy weapons.
* In ''TabletopGame/MyriadSong'' pretty much all EnergyWeapons other than LostTechnology Xenharmonics get hotter as they are used, fortunately they have a "Cooldown" dice that has a chance of reducing the heat level at the end of the turn.

[[/folder]]

[[folder: Video Games ]]

* Happens with Covenant weapons in ''{{Halo}}'' that don't have to be reloaded. Those weapons also need to be replaced after they run out of ammo.
** Same thing in the fan game ''HaloZero''.
** Mounted machine guns function this way in ''[[HaloReach Reach]]''. When mounted, they overheat, but when torn free, they can be fired nonstop until their ammo runs out.
* The beam laser in ''{{Forsaken}}'' breaks if it overheats.
* In the shooter minigame in ''FinalFantasyVII'' the laser becomes less and less powerful if used continuously and you must wait for it to recharge.
* Many of the guns in ''StarWars: [[StarWarsBattlefront Battlefront]]'' follow this trope. Your backup pistol has unlimited ammo, but overheats quite quickly (and has less power than any other weapon in the game, so using it is ill-advised); vehicle-based weapons all have some sort of heat meter, and the Clone Commander's chaingun in ''Battlefront II'' uses the overheating mechanic to avoid becoming a GameBreaker.
** The V-Wing's cannons in ''RogueSquadron'' overheat rather quickly in rapid-fire mode.
* Happens in ''Franchise/MassEffect'': All guns use 'mass-accelerator' technology to shear off a piece from a block of metal inside the gun and accelerate it when fired. As the technology only needs a small piece to have a lethal amount of force, this allows guns' blocks of metal to be sufficient to fire thousands of shots and culminates in ammunition being a non-issue in-game - guns still generate heat though, and thusly creating the {{Overheating}} system inside the game. Certain upgrades and ammunition will increase the rate at which the guns overheat, others will lower it.
** Though it should be noted that with adequate equipment, you can easily make it so the guns will ''never'' overheat. Alternately, make it take a very long time to overheat and add some firepower. The Infiltrator class has the ability to lower the heat output on firing weapons which when combined with damage upgrades makes the class output the most damage over time in the game.
** It is, however, thoroughly impossible to do so with any weapon using High Explosive Rounds, as they generate +500% heat.
** Alternatively, go the other way and cram on extra-heat, extra-damage mods onto your SniperRifle and accept the fact it'll overheat after every shot, essentially making the equivalent of a cannon. Which begs the question: aren't any parts being damaged by being subjected to +550% over standard heat on a regular basis?
** In the background, it's also a major concern for the player's ship, the stealth frigate ''Normandy''. Not so much from weapons (they do generate a lot of heat, but it's easily dealt with), but from its [[StealthInSpace thermal cloaking]], which prevents enemy ships from getting a reading on its heat signature by, essentially, trapping all of the ship's heat in massive heat sinks. As the ''Normandy'' continues to remain cloaked, the heat builds up to noticeable levels, and eventually it has to decloak before the crew begins to suffer from the higher temperatures.
* ''VideoGame/MassEffect2'' went for a system that works like a typical shooter with limited shots before reloading. They attempt to reduce the degree of {{retcon}} by explaining it as ejecting the heat sink of your gun and inserting a new one. Which, naturally, should prevent you from [[OneBulletClips reloading single shots into a gun that fires multiple shots per heatsink]]... but doesn't. And while it would make sense to be able to wait for the heat sinks to cool and use them again instead of throwing them all away and trying to scavenge new ones, that's not an option. Of course, all this only applies to ''you''. [[TheComputerIsACheatingBastard Computer-controlled]] characters still have BottomlessMagazines. GameplayAndStorySegregation is in full effect here.
** This is [[JustifiedTrope justified]] by explaining that the heat sink system allows the shooter to fire more bullets in a shorter time without waiting for the gun to cool down. Also the heat sinks are filled with a lithium compound that chemically changes when absorbing heat, so waiting for the sinks to cool is pointless.
* ''VideoGame/MassEffect3'' brings back several overheat weapons.
* In the ''{{Mechwarrior}}'' games, this is an inherent gameplay trait. All weapons create heat that must be dissipated by your 'Mech, but energy and missile weapons cause the most heat. Heat sinks can help dissipate the heat generated, but there's still a danger of overheating, and once you pass a certain threshold the 'Mech engages an automatic shutdown. If you override this automatic shutdown[[note]]or if your 'Mech is forced into critical overheat too quickly for it to trigger[[/note]], you run the risk of [[MadeOfExplodium ammunition explosions and reactor meltdowns]]. In ''Living Legends'', going past the shutdown heat while overriding will cause your armor to literally melt off, generally starting with both arms. If you mount a Gauss rifle in either arm, [[MadeOfExplodium it'll explode when destroyed]].
** However, that really applies only to energy[[note]]lasers, particle cannon, flamethrowers[[/note]] and missile[[note]]rockets, guided missiles[[/note]] weapons: ballistic weapons[[note]]cannon, machine guns, gauss rifles[[/note]] generate (almost) no heat at all, the only exception being the gatling-style Rotary [=AutoCannon=], which overheats distressingly quickly.
** This is an important part of the CompetitiveBalance of the various weapons, usually weighed against its ammo stock: laser weapons have BottomlessMagazines but build up heat quickly, making them ideal for a long but low-intensity fight, whereas ballistic weapons had little heat buildup and fired rapidly, but ran out of ammo in a longer engagement. In addition, a mech could spend tonnage on "heat sinks" that increased the rate it cooled down at, allowing it to mitigate the heat of its weapons at the cost of having fewer of them.
* The Sten and [[GatlingGood Venom]] of ''VideoGame/ReturnToCastleWolfenstein'' are rare examples of overheating weapons that still have limited ammo. [[TheComputerIsACheatingBastard This doesn't affect]] the EliteMooks who wield them, however.
* ''VideoGame/YoshisSafari'' had the, uhm, Super Scope overheat.
* In ''VideoGame/Left4Dead'', both the mounted guns overheat in about seven seconds of continuous use, and take about 20 to cool down enough to be fired again.
* ''VideoGame/TimeSplitters'' and its sequels use this with the chain gun and plasma rifle, among others. The former even allows you to keep the barrel constantly rotating without firing (which keeps the heat gauge on about 1/3) so you can start shooting more quickly at the cost of overheating faster.
* The vehicles in ''VideoGame/{{Prototype}}'' have their machinegun/miniguns do this (they have infinite ammo in missions where you need to use the vehicles or lose).
* In ''VideoGame/AlienVsPredatorCapcom'', each character's built-in guns could overheat, but recharged over time. Except for Linn Kurosawa's, which didn't have any cooldown, but when it ran out of ammo it reloaded very fast (though Linn was helpless during the reload).
* In the ''VideoGame/{{Battlefield}}'' series, mounted weapons generally use an overheat system, while weapons carried by the players have anywhere from 30 to 200 rounds, that can be fired off in one long burst before reloading. The anti-air rotary cannons will overheat and have unlimited ammo, while light machine guns mounted on a tank will overheat, one upgrade for tanks is a 50 cal heavy machine gun which does not overheat, but instead fires much more slowly.
* In ''VideoGame/CallOfJuarez'', there are rusty weapons and normal weapons: the former overheat if you fire them too often and after you fire enough times, the latter only do the last part. Once a weapon overheats, however, it's no longer usable.
** Sometimes it overheats, sometimes it just catastrophically fails, like the barrel rupturing or the cylinder exploding. Also, any normal gun will become rusty and eventually fail the more you fire it.
** The horse-riding SprintMeter in also inverted to function this way: in one (awesome) chase scene, it can be helpful to switch horses because the one you start with will tire.
* In ''VideoGame/GearsOfWar'', the mounted and man-portable machine guns will overheat and require you to "vent" it by using the Reload button. [[GuideDangIt The game doesn't bother telling you that you can do this.]]
* In ''VideoGame/Sly3HonorAmongThieves'', you drive a machine-gun-mounted gondola in a few missions. Using the machine gun too much will stop you from using it.
* Mounted guns in ''VideoGame/FarCry2'' will overheat if fired for too long; however, the portable version of the SAW light machine gun will ''never'' overheat, instead requiring reloads and having ridiculous muzzle climb.
* In ''[[VideoGame/FirstEncounterAssaultRecon FEAR]] 2'' the player is at one point given control of an automatic mounted grenade launcher, which will overheat if fired for too long. Oddly, though, if the player taps the fire button instead of holding it, the heat gauge will never increase.
** The power armor machine guns also overheat after continuous firing and can be seen glowing in thermal vision.
* This is how Dwarven Technologist Janos' {{Mana}} Meter is explained in ''MageKnight: Apocalypse''. He starts with zero heat, gains heat whenever he uses a skill, and when heat reaches 100, he must wait or use a 'coolant' potion.
* Similarly, in ''VideoGame/FreedroidRPG'', Tux heats up from "casting spells" (computer programs) and will fry if he gets too hot. Hence, single-use coolants and items with "Cooling" (heat capacity) and "Cooling per second" attributes.
* Mounted guns in ''VideoGame/{{Killzone}} 2'' overheat, with the meter being the visible top surface of the barrel, which goes from dull silver to bright red.
* Machine guns in ''VideoGame/{{Crysis}}'' can overheat, and the ice-shard firing MOAC gun also works this way.
* Happens in ''VideoGame/ResidentEvil5'' when you continuously firing the Humvee machine gun for too long.
* Your entire mech can have this problem in ''VideoGame/ArmoredCore 3''. It was quite the ScrappyMechanic.
* In ''VideoGame/RobotechBattlecry'', your Veritech's machine gun has infinite ammunition, but overheats after a few seconds. The Battloid's sniper mode lets you fire a ChargedAttack that does more damage but instantly overheats the gun.
* A core mechanic of the Amiga game ''Walker''. Your HumongousMecha is armed with twin guns that overheat if you fire them for too long, then they shut down until cool enough again. You don't really want this to happen when a wave of enemies is bearing down on you.
** Given that this game was released in 1993, it might be the earliest example of this trope in a video game.
* ''VideoGame/{{Warhawk}}s'' have unlimited machine gun ammo. But their guns will overheat and temporarily jam after only a few seconds of continuous fire.
* ''VideoGame/TheSuffering: Ties that Bind'' featured sections with vehicle mounted guns that would overheat. These weren't used for regular fights, only when the game was throwing wave after wave of enemies at you.
* The first ''SoldnerX'' game discourages constant fire by having your weapons overheat after prolonged firing.
* GrandChase does this with Mari's GunSlinger job. The "heat gauge" fills up each round fired and will start to drain out if you stop shooting. If the gauge fills up all they full, the gun doesn't fire at all for a short time, leaving you with an attack that does nothing. However, it does not disable your [[SpecialAttack MP Attacks]] at all, but only one of those uses the gun anyhow.
* ''VideoGame/{{Brink}}'' has the 'ordinary guns need reloading, wall-mounted machineguns overheat' variant.
* In ''VideoGame/GuiltyGear XX #Reload'', Robo-Ky's tension meter is replaced with a unique power gauge and heat gauge. Specific moves increase his heat gauge, and if it maxes out he explodes, causing damage and knockdown to himself. However, his forward+hard slash command vents the heat in a cloud of steam, and it becomes more damaging the closer the heat gauge is to maximum. It's possible to chain together multiple vents before the gauge empties and the attack becomes ineffective again, though typically only one vent is necessary to bring Robo-Ky's heat back to safe levels.
* In the ''MetroidPrime'' series, if you fire your Power Beam rapidly for an extended period it overheats and steam flows out of your gun. It doesn't affect your ability to fire and is purely cosmetic, however.
* Happens in ''VideoGame/{{Persona 3}}'' to Aigis herself after being in Orgia Mode for a full three turns.
* In the ''VideoGame/{{Boktai}}'' series, your Gun Del Sol will overheat if you stay in intense sunlight for too long, causing it to jam temporarily, and take a short while in the shade (in-game or in real life) to cool down and allow it to fire again. Doing it this way prevents the player from regenerating their solar gun's energy near-instantly, and dissuades them from staying outside in intense sunlight for long periods, since the games use an UV sensor.
* ''VideoGame/CallOfDuty 4: VideoGame/ModernWarfare'' has the variant where mounted M249's, miniguns, and the Mk 19 have infinite ammo but can overheat, while the man-portable version of the former does not overheat but has limited ammo. Other games in the series, like ''World at War'', have a variant where you can actually carry around mounted machine guns like the [=MG42=] and mount them on their bipod yourself, but they still have limited ammo when mounted, and in some games in the series will overheat when fired like that anyway.
* ''VideoGame/DeusExHumanRevolution'': the Heavy rifle (which would be more accurately called a light machine gun) overheats if you fire it for too long. A mod specific to that weapon is an enhanced cooling system that slows this down.
* In ''{{Evolva}}'', you have unlimited ammo for your attacks once you get them, but you must wait for them to charge again if you use them for too much time.
* ''VideoGame/TeamFortress2'': the [[{{Zeerust}} Dr. Grordbort]] weapons are overheating-type weapons in all but name. They have unlimited ammo, but must still be "reloaded" after four shots.
* VideoGame/LeagueOfLegends has one champion, Rumble (a dude in a Mech-Warrior type suit), whose [[ManaPoints mana]] mechanic is an Overheat bar. Each ability use adds to it, and when it reaches 100% he overheats and cannot use abilities, but does some increased damage. There is skill in balancing the bar, keeping it full but not overheating until the opportune moment.
* ''VideoGame/Warhammer40000SpaceMarine'' has plasma weapons that overheat after several shots in quick succession or after firing a ChargedShot and have to be vented. Several heavy weapons available in multiplayer also overheat after extended firing.
* In ''VideoGame/GhostRecon: Advanced Warfighter'', vehicle-mounted miniguns and stationary machine guns both overheat if fired constantly for too long.
* ''7.62 High Caliber'', among many other bits of realism, allows any fully automatic weapon to overheat from continuous firing. An overheated weapon wears out faster if you continue to fire it, resulting in a higher risk of jams that need to be cleared. Spare barrels are available, but only for specific weapons (and rarely showing up at all even at levels where such machine guns start appearing), and they take up weight and inventory space for the merc carrying them.
* While overheating is not an actual gameplay mechanic, firing the minigun for long enough in ''VideoGame/SeriousSam'' will cause smoke to rise from the open end of the barrels once you let go of the trigger. NETRICSA's description for the laser gun also mentions that avoiding this is why it's made out of titanium and has four barrels that fire in succession.
* Sharna, your {{BFG}}-wielding medic in ''VideoGame/{{Xenoblade}}'', uses heat as a reverse ManaMeter. Using combat arts fills her heat meter, which only empties when it fills up or when manually vented. While the venting process does leave her immobile and vulnerable, she has the sense to duck while doing it, reducing monster aggro, and the ether effluence actually heals her as long as the heat is draining.
* ''Videogame/RedOrchestra'' has overheating machine guns, but handles it realistically with barrel switching, although not all LMGs have a spare barrel. In Red Orchestra 2 ambient temperature is taken into effect, barrels overheat faster on summer maps. The tank barrels supposedly also heat up, affecting shell velocity.
* ''VideoGame/{{Hellsinker}}'' discourages "fire forever" tactics commonly seen amongst shmup players by using the Luna system. As you fire your main weapon, your Luna gauge decreases, causing your firepower to decrease until it's reduced to minimum level; you can reload the Luna gauge by collecting purple Luna chips or letting your main weapon rest. Kagura's Xanthez equipment in particular is limited to 240 shots, and has full functionality until it runs out of ammo, at which point [[EmergencyWeapon it's reduced to two weak streams of bullets until it reloads all the way back to 240]].
* ''VideoGame/EtrianOdyssey IV'' provides an example with its final class, the [[spoiler:Imperials]]. Their [[{{Magitek}} drive]] [[{{BFS}} blades]] can be used to dish out truly phenomenal amounts of damage, but must cool off for a number of turns after their most powerful attacks. Initially, the cooldown period is as long as 9 turns, but this can be mitigated with the right set of abilities.
* ''VideoGame/EVEOnline'' has overheating of ship modules via the Thermodynamics skill; however, this is more ExplosiveOverclocking as it is intentionally activated by pilots for a boost in module performance. All modules, including weapons, can be activated indefinitely so long as the ship has sufficient [[ManaMeter capacitor reserves]].
* In ''VideoGame/TheOldRepublic'', the Bounty Hunter class uses Heat as a mechanic; using most abilities generates heat, which dissipates over time according to your current heat level. (The higher your heat is, the slower it dissipates, which encourages players to be frugal in normal gameplay while having a reserve for "burst" situations.) However, the actual mechanics of which abilities generated heat [[CompetitiveBalance could be a little odd]]; throwing a sticky grenade caused heat, for instance, as did ''punching someone'' (admittedly, it is a jet-pack-assisted punch), but firing your blasters normally didn't.
* Sega's 1981 arcade game ''VideoGame/AstroBlaster'' gives your ship a laser that is capable of overheating. Fire too many shots for too long, and your laser will be temporarily deactivated.
* In ''{{Vanquish}}'', melee attacks, boosting, and BulletTime cause Sam's PoweredArmor to overheat if used too long, leaving you defenseless while it cools down.

[[/folder]]

[[folder: Real Life ]]

* Overheating weapons will reach a point at which they are incapable of firing- Particularly seen in light and heavy machine guns, which fire large volumes of rounds at a time (the typical belt size is 200 rounds). There are two reasons for this: First, steel expands when it gets sufficiently hot, causing stoppages (ie 'jamming') as the round travels through the bore (which is now too small for it to pass through). The other is that, since the barrel has a substantial weight, when it reaches higher temperatures it will in fact begin to bend, causing similar stoppages. Firing a gun to the point that it is severely overheated will eventually destroy the barrel in several ways. To prevent this, machine gunners carry spare barrels which they switch out after a certain number of rounds (or in a battle situation, 'whenever you have a chance'), allowing one barrel to cool while the other is in use.
** That's the theory, anyway. When the barrels for a given machine gun are returned to an armorer, it's often found that one is a lot more worn than the other(s), indicating the gunner did not swap them often enough.
* This can happen to repeating weapons with wooden furniture around the barrel if they are fired too much too rapidly without having a chance to cool off. Classic AK's are the guns most notorious for doing this. However, you pretty much have to be trying on purpose to do this.
* Averted with the [[TonkaTough Nokia-reliable]] Vickers machine gun. It was so well cooled that the barrels could last around an hour of continuous fire. "Continuous fire" as in: belt feed the weapon for a full hour.
** Provided that you can keep up the supply of cooling water. One famous barrage at the Battle of the Somme involved multiple machine guns firing a cumulative total of not quite one million rounds over 24 hours, which soaked up all the water set aside for cooling, much of what had been set aside for drinking, and all the local urine tubs, and involved a hundred (carefully planned) barrel changes to various guns at various times. The actual reciprocating mechanisms were still ticking over nicely at the end.
* The U.S. Navy is attempting to design a functional [[MagneticWeapons railgun]], and one the biggest issues they need to overcome is that the heat generated from firing warps the rails which severely limits the functional life of the weapon.
** This is also a major limiter for hand-held laser weaponry... modern lithium batteries, capacitors, optics and indeed laser devices themselves are quite capable of delivering enough punch to be dangerous but at such a slow fire rate as to be useful only for research. Fire them fast enough to cause enough damage to compete with projectiles and you'll need a portable water cooling and chilling system far more bulky than any heavy machine gun. For now...
* The modern desktop computer processor (be it a CPU or a higher-end GPU) creates enough waste heat to destroy itself in seconds if not properly cooled. A graphics card with a damaged or non-functional cooling system can easily reach over 100 degrees Celcius (hot enough to boil water) when under any kind of heavy processing load.
** Most CPUs after the mid-2000s have been designed to lower the clock speed at ~80C (or if that fails, shut down altogether at 100C) to prevent being damaged this way. In 2001, [[http://www.youtube.com/watch?v=BSGcnRanYMM you weren't so lucky]].
* There is a story about an army band who (in keeping with regulations) had to do target practice including with machine guns, but due to inexperience they tended to keep firing for too long which would overheat the barrels and damage the guns. Finally, the range master realised that they were better musicians than they were machine gunners, so he mounted a piece of sheet music on the guns consisting of two bars of music showing one whole note followed by one whole rest. Result: No more damaged machine gun barrels and a trope averted.
* [[http://www.youtube.com/watch?v=eNAohtjG14c Here]] is a video in which a man fires 300 rounds through an AK-47, causing the wooden foregrip to catch fire.

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