Includes: Siege Series Dual Ring Scope Mount with Anti-Cant Level Bubble Materials: 6061 Aircraft Grade Aluminum Compatibility: Rifles with Picatinny rails Weight: 5.00 oz Diameter: 30mm Length: 5 in Base Length: 5 in Color: Black Warranty:Lifetime All new rigid unibody design with strategically placed lightening cuts to reduce weight and an integrated anti-cant level bubble to check for level alignment of your rifle before each shot. Imperfect vertical alignment of your scope when shooting introduces scope cant error - horizontal drift of your shots due to cant. An anti-cant level bubble corrects for this issue, allowing you to quickly ensure for proper alignment of your rifle.