Game Reaper 2 Signature Series two piece scope mounts fit long and short actions some super short actions left and right handed guns. Features machined from 6061 T6 aluminum internal ring and base design allows for extra eye relief adjustment reduces scope damage from tightening rings no moving parts between the firearm and the scope up to four times the threads of other mounts for absolute strength and security and absorbs shock and withstands temperature extremes better than steel mounts at a fraction of the weight. Base screws are 8-40 X 1/4 long and use a 9/64 Allen wrench. Ring screws are 6-40 X 5/8 long and use a 7/64 Allen wrench.