Designed to fit most .22 dovetail grooved receivers. Adjustable attaching system. No drilling and tapping required. No drilling, tapping or modifications required. Internal micrometer adjustments with positive clicks. Will fit widths as wide as .600 and as narrow as .300. For a low line of sights. Lock-screws secure adjustments against accidental change. Mounts low but may require a higher than standard front sight.