Auto-Winding 800 Round High Capacity M4 Magazine by JG

This is the ultimate high capacity magazine for M4s because it winds itself! With this mag you will no longer have to stop shooting because you have to wind up your magazine. This battery powered magazine holds 800 BBs and automatically continues to feed them for as long as you keep shooting. The magazine is rechargeable and includes the required charger, so you do not need to purchase batteries for this mag.