Magpul Industries L-Plate, Fits Aluminum USGI 30RD 5.56MM Mags, 3 Pack, Black MAG024-BLK The Magpul L-Plate is a floorplate replacement for current issue aluminum USGI 30-round magazines that incorporates a rubberized pad. Bumper pad is made of durable Santoprene rubber overmolded onto a stainless steel plate.