With twice the capacity of our Single Mag Cases the Double Mag Cases have a built-in tension spring that securely holds magazines of various sizes. An adjustable belt-clip hook accommodates belts of different widths. Built-in tension spring securely holds magazines of various sizes. Includes belt loops and belt clip. Curved to waistline for slimmer profile. Fits 9mm/.40 cal/.45 cal/10 mm/.357 Sig.