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.This model is compatible with.9mm/.40 s&w/45acp/10mm/.357 sig double stack magazine.Type: Magazine HolderColor: BlackMaterial: Carbon FiberSize: AdjustableModel: DoubleFinish: SmoothModel Fit: 9mm/40 Cal/45 Cal/357SigMount Type: Loop & ClipBelt Size: Up to 2.25"Caliber Or Gauge: 9mm/10mm/40S&W/45ACPCompartments: 2