The Heckler & Koch H&K MP5 AEG Magazine is an essential upgrade for airsoft enthusiasts who don't want to constantly reload in the middle of battle. This high capacity magazine can hold up to 8 times the amount of ammo as its standard-sized counterpart. The magazine features an easy spiral winding dial that allows the right amount of tension necessary for smooth feeding. The Heckler & Koch H&K MP5 AEG Magazine is compatible with: GSG 522 ICS (item # CG13921), H&K MP5 A5 Tac SWAT (item # HK-2279015), H&K MP5 A4 Elite (item # HK-2279010), and H&K MP5 SD5 (item # HK-2279013). This magazine is not recommended for use with the HK-2262036, HK-2273003, HK-2273020 and HK-2273002 Dual Power Airsoft Rifles .