Evolution Gun Works HD Tactical Aluminum Rings 30mm diam .850IN. High. The rifle scope rings are machined two at a time to ensure identically sized openings. The 30mm Rifle Scope ring opening is machined to tolerances of +-0.0014 to prevent any damage to the rifle sight tube. Cross bolts are made of chromoly steel. Evolution Gun Works 30mm Scope Rings are finished in anodized matte black and are available in three sizes to fit multiple gun scopes. These Evolution Gun Works scope rings are part of the Rifle Scope Mounts Rings and Bases selection available through our online store. Specifications for Evolution Gun Works HD Tactical Aluminum Rings 30mm: Ring height Evolution Gun Works scope rings 2700: 0.990" EGW scope rings 61000: 0.840" EGW scope rings 2702: 0.850" EGW scope rings 2704: 1.275" Features of Evolution Gun Works HD Tactical Aluminum Rings 30mm: Machined from aircraft-grade aluminum Chromoly steel cross bolts Package Contents: Evolution Gun Works HD Tactical Aluminum Rings 30mm EGW 30mm Tactical Aluminum Rifle Scope Rings Black 0.850in High - 61100