One-piece high-strength body design for better scope alignment Made of heavy-duty quality aluminum alloy Two integral 30mm rings with 1 size inserts(installed as shown in the picture) Offset design makes it to set up the scope eye relief Center height: 1.58 (40mm). Good for Magnified optics scopes with an objective lens size up to 60mm Attaches to Picatinny rail. Locks firmly in place with a 1/2 hex screw Ring width: 0.62 (front to back) Opening between rings: 2.16 Overall length: 3.43 Base rail length: 2 Weight: 4.6oz Recoil lug: cross-slot steel bolt shaft Anodized black matte finish Kit includes an extra ring top with an accessory rail for use with accessories such as a laser sight.