Stun Grenade

The Stun grenades is a grenade in Call of Duty 4: Modern Warfare and Call of Duty: Modern Warfare 2. When it explodes, it temporarily blinds anyone in its blast radius, greatly slows victims down and does a small amount of damage.

Tactics
The stun grenade is most often used around a corner or thrown through windows, where the corner or window sill will prevent the thrower from being stunned. It is typically used in close quarters combat to allow the player to kill dazed enemies easily. Affected targets move and turn considerably slower than normal making it hard for them to aim or evade fire. There is an initial flash but vision is quickly returned. If within the radius, the player throwing it will be affected by the grenade, but not his teammates (unless friendly fire is turned on). The effect radius is smaller than the Flash grenade but makes all targets in the radius extremely vulnerable. Players with 3 may throw them all at the single location, allowing them to travel a moderate distance before the stun effects wear off. A good tactic is use to equip them with a riot shield and a throwing knife and when you see someone you throw the stun grenades run up to the enemy and finish them with the throwing knife. Some players use this weapon because it deals a small amount of damage to its target, thus indicating to the thrower whether or not a target has been stunned. Stun grenades can also be used to slow enemies at the beginning of a Search and Destroy round. Because enemies will not be able to rush or take positions as quickly, it can put them at a significant disadvantage in certain situations. A common tactic used to get kills with explosives is to throw a stun grenade into a crowded area and then fire or throw an explosive into the stunned area. Because the enemies move slower, they are easier targets and can't run from uncooked frags/semtex as easily. Additionally, killing stunned enemies using explosives does not expose the thrower to direct enemy fire if the enemy happens to be pointing in the right direction.

The Stun Grenade is preferred more than the Flash Grenade because not only does it blind the enemy (but not as long as the Flashbang's blinding effect), but also slows the enemy's motion.

A direct impact from a Stun or Flash grenade will always kill somebody that is in Last Stand. Also, in Hardcore game modes like Hardcore Search and Destroy and Hardcore Team Deathmatch, a Direct Impact hit from a stun grenade is enough to one-shot anyone at full health unless they're using Juggernaut. Although it is extremely rare, stun or flash grenades explosions can kill a heavily wounded target, as it does 1 damage. If you cook a stun grenade in and go into Last Stand, it will turn into a frag grenade. Stun Grenades will not go off in mid-air if you throw them straight up like flash grenades would; rather, they will go off after they hit the ground.

When a player is stunned by an enemy, a sometimes viable tactic is to throw a stun grenade back at the enemy. Because the stun time is dictated by the distance from the center of the blast, if the enemy is closer to the new blast, they will be stunned longer than the player, giving the player a chance to recover and counter attack.

In Modern Warfare 2, wearing a Blast Shield negates the slowing and blinding affect of stun grenades, giving Blast Shield wearers a significant advantage in indoors fighting. The same benefit is received from a Riot Shield.

This grenade actually possesses elements of a flash, frag, and smoke grenade together; the grenade creates a small flash, does a little damage, and creates a negligible amount of smoke (although the flash grenade does so too). The slowing effect is its own unique property.

Trivia

 * In the Wii version of Call of Duty 4, players are still able to turn at their normal speed, making stun grenades much less useful.