Springfield Armory XDM 3.8" & 4.5" CO2 Airsoft Pistol Magazine 25 round capacity Compatible with both compact (3.8") and full-sized (4.5") XDM Airsoft Pistols Houses one 12-gram CO2 cartridge Note: Using this CO2 magazine instead of the Green Gas magazine in your Springfield Armory XDM Airsoft Pistol will increase the velocity to approximately: 350 fps with .2g BBs (3.8") and 370 fps with .2g BBs (4.5").