The Umarex CO2 Adapter allows airgun shooters to use two 12 gram CO2 cartridges in place of one 88 gram tank on most 88-gram CO2-powered airguns, like the Umarex AirJavelin and 850 AirMagnum. 12-gram CO2 cartridges are much easier to find in retail stores than the 88-gram tanks and they also offer shooters more flexibility, especially when only wanting to take a few shots. Prevents wasting unused portions of an 88-gram cartridge. This adapter will work well with the Umarex AirJavelin, Hammerli 850 AirMagnum, and other CO2-powered airguns and air rifles made for 88-gram tanks.