Gas HFC 134a / 144a (PREDATOR 144a) is suitable for weapons of Japanese manufacturers (Tokyo Marui, MARUZEN, Marushin and WESTERN ARMS). Propellant called "Green Gas" is suitable for Chinese and Taiwanese (KWA / KSC) weapons. These can be found under the name Ultra Air Power Gas, Predator Ultra Gas and strongest Brut Sniper Gas. The last type of gas guns are designed for cartridge-type CO2. Weapon which use CO2 gas has high muzzle velocity, but the internal parts are more stressed, which means lower lifetime of these weapon.