Sig Sauer Alpha2 30mm, 1.53in Medium Rifle/MSR Mount – Sig Sauer proprietary steel alloy ALPHA2 Scope Mounts are machined with an exactness that is both strong yet ductile that allows their rings to form around a riflescope, yet will not damage scope under proper installation. The steel rings are epoxy powder coated to prevent oxidation and resist gun oils, cleaning solutions, and outdoor exposure.