Get a clearer sight picture and more accurate crossbow using a HHA SportsTM Crossbow Speed Dial Scope Mount. Patented R.D.S. (Range, Dial, Shoot) Tape Technology gives TO-THE-YARD accuracy on distances from 20 to 80 yards. The time-tested method of two-distance sighting is fast and easy without guessing or "gapping". 48 different calibrated yardage tapes for bow speeds from 260 to 410 F.P.S. matches most high-performance crossbows. Rock solid CNC machined aluminum construction easily piggybacks on any standard Weaver® style rail with 2 pins and adds only minimal height and weight to your set up.