Leupold steel Standard (STD) rings and bases are the most versatile of any mounting system we offer. This specific ring model fits any riflescope with a 30mm maintube and is meant to be paired with our Standard bases. It is the perfect choice for calibers less than .300 Win. Mag. STD rings come in five different heights and are precision engineered to match up with STD 1-piece or 2-piece bases. The front dovetail ring pivots, allowing for lateral adjustment using the rear windage screws while bore sighting. Shims can also be used, reserving the scope's elevation adjustment for BDC (bullet drop compensation) dial applications.