Monstrum Offset Cantilever Dual Ring Scope Mount Black 1in. The offset design provides an additional 2 inches of forward extension allowing extra flexibility for optimum eye relief and shooting position. The mount is 5.75 inches in total length. The base is 3 inches long with the mounting bolts spaced 2 inches apart a minimum of 3 inches of rail space is required to install. The height between the top of the base to the bottom of the scope rings is 1 inch providing 1 inch of vertical clearance. The mount is constructed of lightweight 6061 aluminum the mount weighs a mere 9 ounces. Specifications for Monstrum Offset Cantilever Dual Ring Scope Mount: Manufacturer: Monstrum Height: 1.7 in Gun Rail: Picatinny Fabric/Material: 6061 Aircraft Grade Aluminum Distance Between Rings: 2.5 in Tube Diameter: 1 in Ring Height: 1 in Length: 5.8 in Weight: 9 oz Gun Model: AR-15 Additional Features: 2 inches of forward extension allows extra flexibility for optimum eye relief and shooting position Condition: New Gun Type: Rifle Quantity: 1 Features of Monstrum Offset Cantilever Dual Ring Scope Mount Materials: 6061 Aircraft Grade Aluminum Compatibility: AR-15 Rifles with Picatinny rails Weight: 9.00 oz Diameter: 1.00 in Length: 5.75 in Base Length: 3.00 in Package Contents: Monstrum Offset Cantilever Dual Ring Scope Mount Includes: High Performance Offset Dual Ring Scope Mount 2 Thumb Screws. What firearm models does the manufacturer say Monstrum Offset Cantilever Dual Ring Scope Mount is compatible with? The manufacturer says that Monstrum Offset Cantilever Dual Ring Scope Mount is compatible with AR-15Monstrum ZR254-B: Offset Cantilever Dual Ring Scope Mount Black 1in