Features Injection molded polymer body is lightweight but can withstand the rigors of field use Easy to use winding mechanism ensures proper feeding 400 round capacity Metal magazine stem Easy to fill design Provides more firepower than standard extended magazines Huge gas reservoir Specifications: Material: Polymer, Aluminum AlloyCapacity: 400 roundsGas Type: Green GasCompatibility: Elite Force, UMAREX GLOCK and other GBB Pistols w/ VFC Blowback System | SAI BLU, ISSC M22, Lonewolf, ZEV, G&P Custom, P80 and other GBB Pistols w/ WE-Tech Gas Blowback System | Not compatible w/ KWC, WinGun systems