These new mid-cap magazines for the AKR Series AEGs have the ability to change capacity from 30 to 120, so you can move from a training scenario to CQB or Field airsofting! These mags work with the AKR’s mechanical/electrical cutoff, so when you’re out of ammo, the gun will stop firing, indicating the need for a replacement mag! Combined with the kick that the Kinetic Feedback System gives with each shot, these mags help give you the most realistic experience ever!