Jebs Choke Tubes 20 Gauge Benelli SBE-11/M2 Crio High Voltage .575 Modified/ Full Waterfowl Choke Tube Black Nitride JPCBN - 20E2/575. The patented design gives the shooter a more consistent shot pattern a more distinctive & shortened shot-stream and incredible knock-down power for those much needed "longer shots" Choke Tubes are offered in Ported as well as Non-Ported models. Specifications for Jebs Choke Tubes High-Voltage Waterfowl 20 Gauge Choke Tube: Manufacturer: Jebs Choke Tubes Fabric/Material: 17-4 Heat Treated Stainless Steel Gauge: 20 Quantity: 1 Condition: New Package Contents: Jebs Choke Tubes High-Voltage Waterfowl 20 Gauge Choke Tube Jebs Choke Tubes JPCBN - 20E2/575: 20 Gauge Benelli SBE-11/M2 Crio High Voltage .575 Modified/ Full Waterfowl Choke Tube Black Nitride