This magazine is made of plastic and fully compatible with aftermarket airsoft guns taking AK magazine. The capacity of this magazine is 500rds and the internal compoments of the magazine are imported from Japan. Extremely smooth loading of the BB means no re-wind is necessary after one full wind up. Non Slip design assist user to hold the magazine more security. 

A.P.S. 500rd Funny Cool Gun Non-Slip Magazine for ASK/AK AEG (Black) 
Polymer Housing Magazine (With Non Slip Texture) 
Suitable for ASK/ AK Series Airsoft Electric Gun AEG Rifle 
Large thumb dial on bottom of magazine for wind up the compression spring to Load up the BB Bullet 
Strong spring system makes sure BB`s are loaded reliably 
500 Rounds Hi-Cap Loading Capacity Magazine