11mm (or 3/8) dovetail-to-Weaver/Picatinny adapter 3.04 clamping & mounting length .69 high 4.12 overall length 4 hex screws secure the base Includes a hex wrench Use on AirForce rifles and pistols or any other airgun or rimfire that has a 3/8 or 11mm dovetail. Weaver/Picatinny scope bases offer a much tighter grip on your scope mounts. This would be an especially good addition to any hard-recoiling spring-piston rifle. The cross slots deliver extra gripping area for the rings, making it almost impossible for the scope mount to shift. You may need to buy two of these adapters, depending on the length of the scope mount you're using and on the length of the scope rail to which you're attaching this adapter.