Briley Mobil Spectrum 12 Gauge Choke Black Oxide Improved Cylinder. Choke constriction is laser marked on color-coded band so there is no need to remove choke to verify size. Long tube with hidden wrench slots extends beyond the length of the muzzle. Knurled grasping band speeds installation and removal. Helical rifled Diffusion spreader tubes provide a pattern that is more open than cylinder. Specifications for Briley Mobil Spectrum 12 Gauge Choke: Manufacturer: Briley Fabric/Material: Stainless Steel Gauge: 12 Choke Tube System: Mobil Choke Gun Make: Beretta Package Contents: Briley Mobil Spectrum 12 Gauge Choke Briley BERSB12IC: Mobil Spectrum 12 Gauge Choke Black Oxide Improved Cylinder