Blackhawk's Double Mag Case Single Stack has a built-in tension spring that securely holds magazines of various sizes. An adjustable belt-clip hook accommodates belts of different widths. Includes both belt loops and belt clip and is curved to waist line for slimmer profile. This magazine case will fit all 9mm, .40 cal, .45 cal, 10mm, and .357 Sig caliber single column magazines, and has a black matte finish.