Umarex's NitroAir is the most revolutionary, innovative, and convenient solution for high pressure airguns. Compressed to 3,600 psi this two-pack has 32 grams of nitrogen (N2) in each cartridge and works seamlessly with the Umarex Komplete NCR, the very first N2 cartridge PCP air rifle. These revolutionary nitrogen cartridges should only be used with airguns that are designated by a N2 symbol indicating the airgun is for use with the pre-filled, disposable nitrogen cartridge. NitroAir cartridges are not for use with CO2 airguns. NitroAir can be used with N2 designated airguns in both hot and cold temperatures. This is a benefit that CO2 does not offer and NitroAir means you don't need an expense air compressor or an airgun hand pump that results in a sweaty workout just to get some trigger time.Features :For use with KOMPLETE NCR Air Rifle32 Grams of Nitrogen Per Cartridge2 Pack