3 Kills - Radar: Deploys a UAV to scan the maps for 30 seconds and reveal enemy locations. Enemies with the second tier perk UAV Jammer will not be detected by the UAV.
5 Kills - Airstrike: Call in an airstrike on a targeted area of the map.
7 Kills - Helicopter: Deploys an attack helicopter, either an AH-1 Cobra or Mi-24 Hind (depending on what team the player is on), to engage enemy players for one minute. It can be shot down with RPGs, launched grenades, or concentrated gun fire.
3 Kills - Recon Plane: Deploys a recon plane to scan the map for 30 seconds and reveal enemy locations. Enemies with the second tier perk Camouflage will not be detected.
5 Kills - Artillery: Calls in eight artillery shells to strike a designated location. Player will experience shellshock if close to where the shells are landing.
7 Kills - Dogs: Calls in a pack of vicious dogs for one minute time. If dogs are killed, more spawn. Friendly dogs appear as tan and black German Shepherds, enemy dogs appear as solid black German Shepherds.
In Modern Warfare 2, players can choose up to three killstreak rewards they can earn, rather than just the standard three. At the start, the player can only use UAV, Care Package and Predator Missile, with the option to unlock one new killstreak at each of the following levels: 10, 15, 23, 35, 47, 51, 55, 59, 63, 66, 68 and 69 (all killstreak rewards will be unlocked at level 69). When a killstreak of 8 or more is activated, a message will notify all players in the match, showing the callsign and the streak being used (except in Hardcore or when the killstreak is a Stealth Bomber being deployed by the opposing team). Even though a Tactical Nuke is announced to both teams, the player's callsign on the top-right corner will only be shown to players on that player's team.
It is worth noting that two killstreaks that share the same killstreak amount cannot be used together, one must be picked over the other. For example, for the 7 kills slot the player can use either the Harrier Strike or the Attack Helicopter, but not both, as well with 9 kills slot the player can use either the Pave Low or the Stealth Bomber and the 11 kills slot the player can choose from either the AC-130 or the Chopper Gunner.
For controllable killstreaks (Predator Missile, Chopper Gunner and AC130), if the player is killed while operating the killstreak, the player can continue using the killstreak until it is done and then respawn or enter spectator mode as normal. The only exception to this is Search and Destroy.
Player must throw a red smoke grenade to mark the location of an air drop package containing a random killstreak or ammo. The package can kill players if it lands on them. Can be taken by anybody. It takes longer for anybody but the user to obtain the package, leaving them vulnerable.
Player must throw a red smoke grenade to mark the location of an air drop package containing an M134 Minigun configured as an automatic M5 sentry gun. The same rules for the care package apply. A single slash from a knife or gunfire will disarm it. Has a 90 second time limit. It can be temporarily disabled by a flash or stun grenade.
Deploys a small airstrike from two Harriers followed by one that will hover over the designated area and attack enemies with its under-mounted turret. Can be destroyed. Will disperse rockets and destroy enemy helicopters as its primary target if there are any in the sky. This will also leave the player vulnerable on the ground until they deploy the harrier.
Deploys a B2 Spirit that is invisible to the enemy's radar. The bomber carpet bombs a specific line, designated by the player. Cannot be destroyed. Players can experience shell shock when near their own or an enemy's bomb explosions and survive (the only time a player experiences it in multiplayer).
Deploys a AH-64 Apache or Mi-28 Havoc attack helicopter, armed with a 25mm cannon, controlled by the player on the ground. The player can be killed on the ground, but, can still finish out the session in the chopper. Can be destroyed.
Deploys a Lockheed AC-130 gunship controlled by the player on the ground. It is equipped with a 25mm Gatling gun, 40mm cannon and a 105mm howitzer, each with an infinite amount of ammunition, but with reload times. The user is vulnerable while using the gunship. Can be destroyed by a launcher or a predator missile. Immune to regular guns. It has 2 flares meaning at least 3 rockets must be shot.
Deploys an electromagnetic pulse that destroys enemy killstreaks and disables enemies' HUDs, mini-map and electronic attachments, such as Holographic Sight. Also disables already deployed equipment, but those deployed after EMP will not be affected.
Calls in a nuclear strike that detonates after 10 seconds, killing all players that are spawned at the time the nuke goes off on the map and ending the match in favor of the nuke user's team, regardless of the current match score or time left (except in Free-For-All, in which the player with leading points still wins). The player gets points for the deaths of the enemies killed.
Black Ops features a similar customizable killstreak reward system to Modern Warfare 2. All killstreak rewards are available for purchase, via CoD Points, at rank 10. Kills from killstreak rewards don't count towards higher killstreaks unlike previous titles, which means that players must kill the required number of enemies themselves. Also, the Tactical Nuke has been removed.
If caught as it approaches, the helicopter dropping the reward crate may be shot down and the killstreak reward lost by the opposing team.
A remote-controlled car strapped with explosives. Controllable for 30 seconds when it self destructs. Can be detonated prematurely by pushing the fire button. 100 XP for calling it in, 80 XP for destroying it.
Airdrop a SAM (Surface-to-Air Missile) Turret. It targets all aerial killstreaks, including Valkyrie Rockets, and has infinite ammunition. 100 XP for throwing the marker, 300 XP for shooting the Sea Knight down and 75 XP for destroying the turret itself.
Airdrop a random killstreak reward, ammunition, a death-machine or a grim reaper. 150 XP for throwing the marker. 300 XP for shooting the Sea Knight down. The crate will NOT be destroyed if the chopper is shot down. Can be "rerolled" with Hardline Pro and booby trapped with Hacker Pro.
Call in a Cobra attack helicopter that can be destroyed. It uses a target map like the Mortar Team or Napalm Strike. Unlike Chopper Gunner and Gunship, it cannot be controlled. 200 XP for calling it in, 300 XP for shooting it down.
A surface-to-air missile launcher with two controllable missiles. Can be used to take down other killstreak rewards. 200 XP for throwing the marker, 300 XP for shooting the chopper down, 100 XP for shooting a launched rocket.
Call in an SR-71 Blackbird which shows enemies and the directions in which they are facing. Unlike a Spy Plane, it cannot be shot down. Ghost and Ghost Pro do not prevent users from being detected by the SR-71 Blackbird. 250 XP for calling it in.
Pilot a Hind helicopter gunship. The pilot has UV-32 rockets and a 12 mm nose cannon. The HUD for the gunship in the mission "Payback" is used for this killstreak. Enemies are highlighted with red squares. 350 XP for calling it in, 400 XP for shooting it down.
In Call of Duty: Modern Warfare 2, killstreaks were originally divided into categories and players could select up to three of them.
In Call of Duty: Modern Warfare 2, the UAV, Counter UAV and EMP are the only killstreaks that do not directly kill enemy players.
In Call of Duty: Modern Warfare 2 there are chatter sounds for a Little Bird killstreaks. However, these killstreaks are cut from final game. Also, chatter sounds for enemy Predator Missile, Sentry Gun and Airstrike can be found in game files, but they're not used.
The Valkyrie rockets, Chopper gunner and Gunship are not included in the Wii version of Black Ops.
In Call of Duty: Modern Warfare 2, if one switches teams on a private match after having earned a killstreak without using the killstreak first, the player will lose the killstreak.
Killstreaks are still destructible after a match ends, meaning if the player fires a rocket or AC130 guns at an enemy aircraft, one can still get points if the match ends before the rocket/round hits.
In Call of Duty: Modern Warfare 2, there's another killstreak called "Tank" - An image of a rank, In the Compass (radar) can be found. Also, a script file of _tank.gsc killstreak can be found too.
In the Modern Warfare 2 Official Strategy Guide, in the Multiplayer section, there is a picture of a Tactical Nuke referred to as "Nuclear Strike", with a photo of a mushroom cloud instead of a radiation logo. In that same picture, the Predator Missile goes by the name "Hellfire".