Nuprol Black Gas 4.0 1L Bottle 10.5oz Gas for Airsoft Guns WE NUPROL 4.0 Ultimate Power 300G (1L) Gas Black - 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