Night Vision Goggles

 are a usable equipment that allow the player to see in little to no light.

Call of Duty 4: Modern Warfare
AN/PVS-7B night vision goggles are available to the player in many levels of singleplayer, and are always available in multiplayer.

During the campaign, they can be used in conjunction with the AN/PEQ-2A laser to see a visible path a bullet will take, which can help with accuracy in some situations. However, this will not work to predict the path of a second bullet fired from the hip will take due to recoil. These may still fly anywhere within the crosshairs.

Using these devices in a dark environment gives a great advantage over opposition, although they can be bulky and cut down peripheral vision. Light flashes from firearms and flares are more powerful and disorientating. They are only particularly useful twice in the campaign: once in the mission Blackout, in the house where the player rescues Nikolai, and once in the mission The Bog, during the fight in the first building.

Night Vision is also available in multiplayer, but there are not many areas where it is needed. It may have some use on the maps Wet Work or Bloc, or in the dark hallways of Vacant if the player's television's brightness and contrast settings are too low.

Call of Duty: Modern Warfare 2
Night vision goggles make their return, but are not used often in single-player and not at all in multiplayer. It seems to have much more contrast, the lit areas glowing profusely, making it especially hard to look at. The only time that they are a major use is in "The Gulag", when night vision is needed to infiltrate the dark bottom cells until they find light again. It's seen again in "Just Like Old Times", only being useful for a few engagement with Shadow Company in the caves, but its use isn't particularly needed. Night vision goggles can also be used in the Special Ops mission Overwatch, but they are not particularly useful. In multiplayer, they have completely disappeared, probably because of the introduction of the Thermal Scope being so useful in dark areas and when smoked, with the fact there are no dark maps in-game.

Call of Duty: Modern Warfare 2 Prestige Edition
Working Night Vision Goggles were sold with the Prestige Edition of Modern Warfare 2, the most limited edition of Modern Warfare 2. They are supposed to look like the NVGs In Call of Duty 4: Modern Warfare, as modeled by Captain Price before Gaz cuts the power during the mission "Blackout". Interestingly, on the box for the NVG's it says, "Issued by Griggs."

Call of Duty: Modern Warfare 3
Night Vision goggles are available in the mission "Stronghold", where they are used at the begging of the level and near the middle. At the begging, they are worn by Yuri and Price while they parachute into the Castle grounds, they are then immediately taken off once they get to the ground. They are put on again in the dungeons of the castle, where they are used to navigate the powerless corridors, until the enemies start using flares, in which they are taken off once again. The player can put them on and off at will, but is not advised in light areas. The Night Vision goggles are also available to Yuri in "Down the Rabbit Hole".

Trivia

 * In The Gulag, if the player switches night vision goggles on right before Roach is hit by debris and Soap fires a flare, the player cannot turn them off and must complete the mission with them on.
 * On the Xbox Live marketplace, the player can buy a pair of Night Vision Goggles for 240 Microsoft Points for their avatar to wear. When the Stimulus Package was released, they were available for free for a limited time.
 * In Call of Duty 4: Modern Warfare multiplayer, when the goggles are switched on they cannot be seen on the game character's eyes.
 * If the player hits the ground after jumping while pulling the Night Vision Goggles up, they can see the mount for a VERY short time. This can easily be seen in slow motion.