Leupold steel Standard (STD) rings and bases offer the most versatile mounting system available. This specific ring model fits any riflescope with a 1 inches maintube and is designed to pair with Leupold's Standard bases, making it ideal for calibers less-than .300 Win. Mag. Comes in five different heights, STD rings are precision-engineered to match up with STD 1-piece or 2-piece bases. The front dovetail ring pivots, allowing for easy lateral adjustment via the rear windage screws during bore sighting. Shims can also be added to preserve the scope's elevation adjustments for BDC (bullet-drop compensation) dial applications. Leupold mounts are built as rugged and dependable as the optics they secure, ensuring a strong and reliable connection between your scope and firearm. With a wide variety of mounting systems to choose from, you're sure to find the perfect match for your firearm and shooting style. Made in the USA and backed by a lifetime guarantee, Leupold mounts are designed to withstand a lifetime of use.