The Rimfire rings are designed to fit a very wide selection of rifles with either a 0.375" or 11mm dovetail. This is made possible by using a solid asymmetrical reversible clamp that can be flipped 180 degrees and used on wider or narrower dovetails for the best fit.The rimfire rings are designed to fit a very wide selection of rifles with either a 3/8 inches or 11mm dovetail. This is made possible by using a solid asymmetrical reversible clamp that can be flipped 180 degree and used on wider or narrower dovetails for the best fit. Features: All steel rings with a horizontally split design and only 1/2 inches wide Asymmetrical reversible side clamp fits a 3/8 inches or 11mm dovetail Securely mounts to firearm with Torx style T-15 socket cap screws, 25 in/lb. of torque recommended