Nuprol Black Gas 4.0 1L Bottle 10.5oz Gas for Airsoft Guns x2 PACK WE NUPROL 4.0 Ultimate Power 300G (1L) Gas Black x2 Pack - COMES WITH FREE BULLDOG AIRSOFT SPEED LOADER High performance gas, designed to operate at lower temperatures (between 3c - 20c) Using this high power mix gives an increase in FPS, GBB efficiency and a harder kick Perfect for Airsoft Players who use Gas Blowback Weapons and Rifles in the winter