American Defense Manufacturing 1-Piece Extra Wide No Offset QD Mount Standard Legacy Lever 30mm Ring Size Black. This is a straight up mount with no forward offset. The rings are spaced farther apart to fit long tube Night Vision and Thermal scopes such as the ATN THOR and similar scopes. The inside ring spacing is 3.86" outside ring spacing is 5.8". It is precision machined from 6061 T6 aluminum and finished in hard coat T3 Mil-Spec anodize. It features the Patented QD Auto Lock(tm) Lever system to accommodate both in spec and out of spec rail systems. Specifications for American Defense Manufacturing 1-Piece Extra Wide No Offset QD Mount: Manufacturer: American Defense Manufacturing Gun Rail: Picatinny Fabric/Material: 6061-T6 Aluminum Offset: No in Gun Make: AR Platform Color: Black Tube Diameter: 30 mm Gun Model: AR-10 AR-15 Width: 3.8 in Additional Features: Standard Legacy Lever Condition: New Finish: T3 Mil-Spec Anodize Gun Type: Rifle Features of American Defense Manufacturing 1-Piece Extra Wide No Offset QD Mount Does not require proprietary tools for adjustment. Can be adjusted with your finger or a flat blade screwdriver. Lever can be configured to lock to the front or the rear. Superior clamping surface to insure maximum rail engagement. Precision machined from 6061 T6 Aluminum. Hard coat anodized for a lifetime of performance. Fully adjustable to fit both in spec and out of spec rail systems. Features the Patented QD Auto Lock Lever system. Package Contents: American Defense Manufacturing 1-Piece Extra Wide No Offset QD Mount What firearm models does the manufacturer say American Defense Manufacturing 1-Piece Extra Wide No Offset QD Mount is compatible with? The manufacturer says that American Defense Manufacturing 1-Piece Extra Wide No Offset QD Mount is compatible with AR-15 AR-10American Defense Manufacturing AD-RECON-SEW-30-STD: 1-Piece Extra Wide No Offset QD Mount Standard Legacy Lever 30mm Ring Size Black