Burris 30mm 1.25 High XTR Signature Rings. Opened but unused. Scope Tube Diameter is 30mm. Matte black, Picatinny attachment type. As Advertised On Website: Prop 65WARNING: Cancer & Reproductive Harm - www.P65Warnings.ca.gov Corrects misalignment caused by off-center receiver holes Corrects for bases or rings being slightly off-center No need for expensive tapered bases or shimming for thousand-yard shooting Rugged, robust aluminum tactical rings save weight and mount on any Picatinny-style rail Each ring set includes two sets of concentric inserts and one set each of the following offset inserts: +/-5 MOA, +/-10 MOA, +/-20 MOA