Machined from: solid 7075 t6 aircraft grade aluminum. Finish: matte black only. Compatible with picatinny or weaver scope rings. mounting hardware: socket head torx screws and wrench provided. Center spread: 3.245". Overall length of mount: 7.458". This mount is made specifically for the tikka t3. . Metric screws are only available with hex heads. Check out the tikka faq page. *the center spread is the distance between the two middle holes, center to center, on your receiver. These bases sit at approximately 0.35 high. Picatinny cross slots run the full length of the rail, which gives the shooter flexibility when mounting scope rings and other accessories. The cross slots are also machined the full width of the mount and gauged to mil-std 1913 specs maintaining tolerances of +/-.002". After machining; the mounts are tumbled and sand blasted. The aluminum mounts are type iii hard coat anodized for long lasting durability. The steel rails are mil spec parkerized for a durable rust resistant finish. compatible with picatinny or weaver scope rings. Add Evolution Gun Works hd scope rings to make it a complete package! from manufacturing to packaging, Evolution Gun Works products are made with pride in the usa.