BKL 1-Pc Mount, 30mm Rings, 3/8" or 11mm Dovetail, 4" Long, Offset, Matte Black 1-piece mount 30mm rings Fits 3/8" or 11mm dovetail 4" long Clamp length: 1.65" Offset mount for additional eye relief Matte black BKL mounts 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. BKL's patented Auto-Centering design overcomes problems caused by varying dovetail or rail widths.