AimSports Shotgun 12G Tri-Rail Barrel Mount Black. The AIM Sports Shotgun 12G Tri-Rail Barrel Mount is built of rugged aircraft aluminum with a durable black anodized finish to provide years of good looks and great service. Specifications for AIM Sports Shotgun 12G Tri-Rail Barrel Mount: Length: 1.5" Weight: 4.3 oz. Features of AIM Sports Shotgun 12G Tri-Rail Barrel Mount: Black anodized aircraft grade aluminum Accepts all standard Weaver / Picatinny 1913 accessories No gunsmithing required Compatible with 12 gauge shotgun Package Contents: AIM Sports Inc Shotgun 12G Tri-Rail Barrel Mount AIM Sports Inc MT025: Shotgun 12G Tri-Rail Barrel Mount Black