The PMAG Minus 10 Round Limiter installs in 20 or 30 round GEN M3 PMAG bodies, reducing the magazine capacity by ten rounds. Designed for sporting and hunting applications, installation of the Limiter is simple, tool-less, and requires no permanent modification of the magazine body. This will NOT make a banned magazine legal! This product is intended for TEMPORARY capacity reduction of PMAG AR/M4 GEN M3 magazines.