The Umarex NitroAir system is an idea the sport shooting world has been waiting for. The N2 Adapter, can easily thread on a NitroAir cartridge for use with your Gauntlet or similar air rilfe. Handy as a backup or for small game hunts in the field. Without a pump. The Umarex Airguns N2 Adapter has M16x1.5 threads on the nitrogen end and 5/8-18 on the regulator end.