Evolution Gun Works Conversion Cone 11/16 x 40 .575 x 40. Cones are threaded to match bull barrels. Once the cone is fitted comps can be changed by simply screwing the new comp on without refitting the barrel each time. Works with Aluminum Titanium Steel or Stainless Steel compensators. OD thread - 11/16 x 40. ID thread .575 x 40. Specifications for Evolution Gun Works Conversion Cone: Manufacturer: Evolution Gun Works Color: Silver Fabric/Material: Steel Additional Features: Cone Package Contents: Evolution Gun Works Conversion Cone Evolution Gun Works 11877: Conversion Cone 11/16 x 40 .575 x 40