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 are precision engineered to match up with STD 1-piece or STD 2-piece bases. The rear ring is secured by windage adjustment screws. They boast machined steel construction and are available in five different ring heights.