WARNING: This insert is ONLY compatible with the Micro Fight MK4 and MK3 Chassis. It is not compatible with the MK2 or MK1 Chassis, nor plate carrier kangaroo pouches. Some people say that Submachine Guns are a thing of the past. Spiritus Systems say to heck with that. It doesn't matter if you are storming the Iranian Embassy in 1980 or raiding a meth lab in the Bayou today, the Spiritus Systems Submachine gun inserts have you covered. Submachine Gun Magazine Inserts enable you to carry 4 magazines in either the front or rear pocket of your Micro Fight Chest Rig, or you can carry 8 magazines by placing a Submachine Gun insert into both the front and rear pockets of your Micr Mfg: Spiritus Systems