READY STOCK SIAP KIRIM 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 mag stem Easy to fill design Provides more firepower than standard extended magazines Huge gas reservoir Specifications: Material: Polymer, Aluminum Alloy Capacity: 400 rounds Gas Type: Green Gas Compatibility: Elite Force, TM, UMAREX and other GBB / VFC Blowback System | SAI BLU, ISSC M22, Lonewolf, ZEV, G amp;P Custom, P80 and other GBB / WE-Tech Gas Blowback System | Not compatible w/ KWC, WinGun systems (AIRSOFT ONLY)