The polymer frame contains steel reinforced rear and front locking lugs as well as steel BHO (bolt hold open) follower and floor plate. These magazines are used by Serbian military special forces and passed rigorous tests. They are tested at high and low temperature ranges and must exhibit consistent strength, resistance to shatter, and lubricity from -40 C/F to +60 C/140 F. Unlike most other polymer mags, the Serbian ones have to pass a loaded military drop test, in a rifle, from shoulder height onto concrete. Fits all AKs using 7.62x39 double stack magazines. Magazines cannot be shipped to IL (Cook County) VT, NJ, MD, NY, CO, CT, D.C., MA