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 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 Ring screws are #6-40 x 5/8 inches long, they use a 7/64 inches allen wrench Made in the USA