Flashbang

The Flashbang is a grenade used in Call of Duty 4: Modern Warfare, Call of Duty 4: Modern Warfare (Nintendo DS), Call of Duty: Modern Warfare 2, Call of Duty: Modern Warfare: Mobilized, and Call of Duty: Black Ops. It temporarily blinds anyone affected by with with a white light and leaves a "ringing" sound in the victim's ears.

Tactics
The Flashbang grenade can be effectively used on a defended location or around a corner. Flashbangs will detonate seconds after being thrown. They cannot be cooked. If the target is close enough or looking at the detonation site from a distance, they will be temporarily blinded and deafened. The target’s reaction is still in real time so they can move forward or backpedal to evade, however, they cannot sprint while affected. They can still fire and knife normally, making any enemy in front of them a potential kill. Affected targets will raise an arm to cover their eyes, signaling to the player that they are blinded.

In the single-player campaign, the player spawns with flashbangs, and can find additional grenades in grenade bags, but they only appear in the bags if the player has already expended some their own flashbangs. In multiplayer, if the player goes into Last Stand while prepping a flashbang it will turn into a frag grenade. Flash Grenades detonate exactly one second after being thrown; they do not have to impact the ground like Stun grenades.

Because it only affects players' vision if they are facing towards it, a viable tactic is to turn away before it detonates or to duck behind cover. Keep in mind that this only works at the outer edges of the grenade's blast radius; a player who is close to the grenade's detonation will be blinded no matter where he looks. Also note that a flashbang's effective radius is cut short by any wall or obstruction, regardless of how much cover it provides. For example, a low wall will defend against a flashbang, even though the grenade is still completely visible. Additionally, the flashbangs inflict a small amount of damage (15 points) if they physically strike a player, which can kill a target with low health.

It is useful, in Modern Warfare 2, to add the Scavenger Perk to it (especially when playing maps such as Favela where there are numerous rooms and buildings player can be in for tactical advantages (or for hiding). By doing this, the player can consistently do a flash-and-clear method of approaching buildings (this is, however, ineffective unless the player is killing enemies to help resupply themselves). For this reason, it is best to do this when there is a higher probability that someone would actually be in the building. I.E. don't flash buildings really close to where the players team is spawning. The probability of someone being in that building isn't as high as someone being in a building further into the center of the map. This also disables claymores set up by individuals to watch themselves while inside the building (ex. snipers). This tactic is best used on the maps Favela and Invasion where house-to-house fighting abounds more than the typical map.

If on a hardcore game type, the player can actually kill an enemy player by throwing a special grenade at their head. It isn't really useful, but will make a good final kill in a Hardcore Search and Destroy, if there is 1 last enemy player left, and they are planting/defusing the bomb. Note: this will only work in MW2 at the moment.

It's worth noting that while stun grenades are used to slow targets down if they intend to run, flashbangs serve better as a way to kill enemies in enclosed spaces. They will be unable to tell if the player has entered the room and any equipment in the room will be temporarily shut down due to the larger range of flashbangs (MW2 only).

Throwing a Flashbang into an area infested with enemies can give the player a great amount of assist points as the Flashbang's explosive radius is higher than a stun grenade. Enemies may also randomly shoot, thus giving away their positions making them more vulnerable.

Versus Stun Grenades

 * In Call of Duty 4: Modern Warfare a flashbang does not indicate if it has affected the enemy, making it difficult to discern whether it has had any effect. Stun grenades, by contrast, show the damage indicator if they've affected anyone, thus making stun grenades more popular. However, in Call of Duty: Modern Warfare 2, flash grenades also produce hitmarkers on successful hits. Note, however, that hit markers will appear if the target is affected by the flashbang at any range, meaning he could be barely hit and only pacified for a very short time. So while the player thinks he is fully blind, he is running into the room to certain death.
 * Flashbangs have a larger effective radius than stun grenades; this is a double-edged sword, as flashbangs are more likely to affect the thrower as well. At the edge of the blast radius, players are blinded and deafened if they are looking in the direction of the flashbang. If they are at the edge, but looking away from it, they will only be deafened.
 * Flashbangs do less damage to affected targets than stun grenades do; a stun grenade is more likely to kill a wounded player.
 * Flashbanged players are blinded and deafened, but still move in normal speed (though they cannot sprint). Stunned players move and aim more slowly.
 * Flashbangs will explode in midair. Stun grenades must impact something solid first.
 * Flashbangs take about twice as long as stun grenades to arm and throw. This makes it more likely that an enemy will encounter the player while deploying one.
 * A flashbang can completely disorient a player, as it blinds them and removes any extravisual perception. Players affected by a stun grenade, however, can still see clearly and react to their surroundings, albeit very slowly.
 * Blast Shield protects users from stun grenades but flashbangs will still blind a Blast Shield user. The same goes for Riot Shield users.
 * Because Stun Grenades slow the enemy, require hitting a surface, have a smaller blast radius, and indicate if a target has been affected, they are used more often than flashbangs.
 * Flashbangs can disable planted C4 and Claymores temporarily. So do stun grenades.
 * In Call of Duty: Modern Warfare: Mobilized, the player can tell if someone has been flashbanged by their movement. If they have, they will be moving back and forth, firing single shots randomly, and covering their eyes.

Trivia

 * The Spetsnaz forces sometimes shout 'ya brosayu flashbang' (I'm throwing a flashbang), this being incorrect. Flashbang in Russian is светозвуковая граната (svetozvukovaya granata).
 * On the flashbang, there is writing which reads: Fuze M-201A1 IW 7-070 M-84 Flashbang.
 * In Call of Duty 4: Modern Warfare, the Flashbang is the first equipment used in the campaign (F.N.G.).