AR15 M4 30mm / 1" Quick Release Scope Mount QD68Works with both 30mm and 1 inch scopes Heavy duty, single unit base, machined from aircraft grade aluminum alloy Offset design for better eye relief position 4 bolt for each ring to secure, shock proof Built in Weaver style rails very handy fitting flashlights and lasers etc. Overall length: 5. 2" Distance between scope ring : 3. 3" Ring size: 30mm 1 (with insert included) Weight: 8 ounces