3/8 or 11mm Tri-mount dovetail riser 1-5/8 long and clamping length .68 riser height .76 overall height 1.7 oz. Auto-Centering overcomes issues with varying dovetail/rail widths Silver finish Designed for semi-auto actions and airgun receivers Formerly BKL-172 * Risers in a silver finish aren't that common, but BKL's got you covered. This BKL Tech riser has 2 extra rails on the sides so you can mount a flashlight or laser in addition to your scope. BKL optical products have the unique ability to flex, giving them superior gripping power! Your mount may look like it's bending, but it's supposed to do that...it's grabbing and tightly holding your optics on your gun.