TSR SL (Super-Low) Series Rings. Providing an extremely low mounting solution for those special applications Precisely machined from an alloy steel billet, with tolerances held to .0002″, give maximum scope/ring contact. Holds scope securely against recoil. Four-screw cap lets you align the reticle, tighten the left side of the cap, then the right side without the scope rotating. Radiused edges and corners help prevent snagging while providing attractive appearance. Large, clamp-nut lets you torque rings to Mil-STD 1913 (Picatinny) bases. SPECS: Alloy Steel, black oxide finish to Mil-C-13924 standards. 5/8″ (15.8mm) wide. Height measured from top of base to center of ring. 30mm – Super-Low: .820″ (20.8mm).