Gas Mask (perk)

Gas Mask is a Tier Two Perk in Call of Duty: World at War that reduces the effects of a Tabun gas grenade, allowing a player to attack enemies affected by the grenades without hindrance. This is the only use for this perk, therefore, it is usually passed over for more useful perks, like Sleight of Hand, Stopping Power, and Overkill, especially since it takes what is arguably the most important perk slot. It is unlocked at Level 2.

Multiplayer Tactics
If you want to use this perk effectively, it is almost necessary to use it with the Special Grenades x3 perk and, of course, Tabun Gas. This combination makes the player lethal when storming buildings, since they will be unaffected by the gas and can easily kill the poisoned enemies inside. Using a close-range weapon for this purpose is recommended. This perk should be used in a class with a fast-paced weapon (such as a shotgun, or SMG) for use in objective based games, especially if there is a point that must be captured, such as in Domination, War, or Headquarters.