Briley Mobil Choke Helix Choke Black Oxide 12 Gauge Cylinder. Lead is tightly bound within the choke limiting any expansion. Lead is kept under control either by chokeing up more often or by using a longer groove length. When using lead choke tubes should be re-focused frequently to assure the best possible pattern. Briley's Helix Lead Alloy Frame Choke Tubes have undergone rigorous quality assurance testing to ensure that they meet Briley's strict standards for performance. Lead allocators feature a unique taper inside the choke that is parallel to the lead allowing the shooter to take lighter loads. After the initial fit-out the Helix Lead Alloy Frame chokes should be re-ooked as needed to achieve the optimum choke-holding section. Specifications for Briley Mobil Choke Helix Choke Tube: Manufacturer: Briley Gauge: 12 Choke Tube System: Mobil Choke Condition: New Features of Briley Mobil Choke Helix Choke Tube Helical Porting Long parallel section ideal for lead or steel Package Contents: Briley Mobil Choke Helix Choke Tube Briley BERHB12CY: Mobil Choke Helix Choke Black Oxide 12 Gauge Cylinder