Leupold Mark 4 AR 30mm Integrated Mounting System Black. Use Leupold PRW bases or any other Picatinny-style mount rails. Specifications for Leupold Mark 4 30mm Riflescope Rings: Manufacturer: Leupold Finish: Matte Base/Mount Type: Riflescope Ring Ring Height: 1.5 in Tube Diameter: 30 mm Ring Quantity: Single Quantity: 1 Ring Type: Ring Set Fabric/Material: Aluminum Length: 6 in Weight: 7 oz Color: Black Distance Between Rings: 3.35 in Objective Lens Diameter: 30 mm Package Contents: Leupold Mark 4 30mm Riflescope Rings Leupold 182860: Mark 4 AR 30mm Integrated Mounting System Black