Vism VR30T13 Tactical Series of 30mm Scope Rings. Fits 30mm & 1" Scope Tube Diameter. Scope Rings come with removable 1" inserts. Mounts onto Weaver/ Picatinny/ MIL-STD 1913 type rails. Hexagon Shape Steel mounting nut, with holes for torking with Allan key wrench. Black Anodized Aluminum Construction Rings sold as a Pair.