Sig Sauer Electro-Optics Alpha1 Hunting Rings Weaver 35mm 6061-T6 Aluminum Extra High Black Matte Sig's Proprietary Aluminum Alloy Alpha Hunting Rings Are machined With An Exactness That Is Both Strong Yet Ductile That Allows Our Rings To Form Around a Riflescope, Yet Will Not Damage Scope Under Proper Installation. Tube Diameter: 35mm Height: Extra High Finish: Matte Material: 6061-T6 Aluminum Mount Type: Weaver