Features: Precision machined from a solid block of top grade billet 6061 T6 aluminum Custom made to fit each Type of firearm and align perfectly with your rifle's receiver No moving parts between the firearm and the scope 67% lighter than comparable one-piece mounts with four times the threads and precision socket-head cap screws for absolute strength and security Absorbs shock and withstands temperature extremes better than steel mounts at a fraction of the weight Right hand mount fits right hand firearms and left hand mounts fit left hand firearms MOA mounts are tapered down on front for long range shooting, height will be about 0.03 inches lower on front ring than a standard straight mount Base screws are #6-48 x 1/4 inches long and ring screws are #6-40 x 5/8 inches long, both screws use a 7/64 inches allen wrench 4-hole to hole spacing dimensions are 0.86, 3.63, 0.6 inches Made in the USA