The Umarex Glock 19 Gen5 MOS CO2 BB magazine is designed for .177 caliber BB gun and holds 17 rounds, allowing for longer shooting sessions without frequent reloading. Get yours today at Airgun Depot for an authentic experience!17 round capacityHolds one 12 gram CO2 cartridgeWeight: .7 lbsCompatible with the Glock 19 Gen5 MOS BB Gun