Airsoft Metal M4 M16 AK Double Magazine Clamp Adjustable
Our take:  JG metal M4/M16/AK magazine clamp, compatible with most-all M4/M16/AK47 magazines.  This magazine clamp is adjustable for fitment on the magazine you have (M4/M16/AK47) and effectively doubles your on-field ammunition capacity.  Please note that the magazines in product photos is not included; It is just an example to show how the mag clamp can be used.