Leupold Mark 4 34mm Super High MatteThese rings are machined from solid steel, they offer superior integrity and tighter tolerances that are based on the proven cross-slot design. Use Leupold PRW bases or any other Picatinny-style mount rails.8-40 Adaptable (Mark 4)Leupold Mark 4 AR-15/M16 Handle MountLeupold Mark 4 CQ/T Flat Top Mounting BracketMark 4 Base Availablilty (Mark 4)Mark 4 Bases Accept (Mark 4)Mark 4 CQ/T A.R.M.S. Throw Lever MountSlot and Spline Design (Mark 4)Height (in) 1.40Ring Diameter (in) 1.34Ring Diameter (mm) 34.00