Rugged, lightweight polymer magazine increases the capacity of your 5.7 x 28mm FN Five-seveN pistol by an additional 10 rounds over the factory mag. Extension is contoured for a smooth, seamless fit to the bottom of the mag well, with exterior texturing that matches the pistol grip's texturing. Mfg: Pro Mag SPECS: Reinforced, injection-molded polymer, black. 30-round capacity. Fits FN Five-seveN pistol chambered in 5.7 x 28mm.