DNZ 21650 Sako A7 Long Action One Tube, 40mm 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 Precision Machined from a solid block of top-grade billet aluminum No moving parts between the firearm and the scope