Elite Tactical Systems Group Magazine, 9MM, 21 Rounds, Fits Sig Sauer P320, Carbon Smoke SMK-SG9-320-21 ETS mags won't crack or break" are resistant to heat" cold" UV and harsh chemicals and won't become brittle over time. Their mags come with enhanced features like non-tilt followers" creep-resistant feed lips and clear body allowing you to see count and ammo type" leaving nothing to chance.