Warne Vapor 1in Med Matte Aluminum Rings fits 3/8-11mm Dvetail. Specifications for Warne Vapor Low Rimfire Ring: Manufacturer: Warne Tube Diameter: 1 in Gun Model: AR-15 Fabric/Material: Aluminum Weight: 1.6 oz Color: Black Mount Type: Picatinny Gun Rail: Picatinny Features of Warne Vapor 1in Aluminum Rings Designed to fit 3/8in rimfire dovetails Time-tested designs Easy to install Field proven performance Lightweight aluminum Lifetime warranty Package Contents: Warne Vapor 1" Low Matte Rings Aluminum Fits 3/8-11mm Dvetail Warne Vapor 1'' Med Matte Rings Aluminum Fits 3/8-11mm Dvetail