STD rings are engineered to match up with STD 1-Piece and STD 2-Piece Bases. Although different ring heights are offered, most hunters and shooters wisely opt for rings that position the scope as low as possible. Manufactures Website Address www.leupold.com Warranty Information Full lifetime guarantee. If any product has defects in materials or workmanship, Leupold will, at their option, repair or replace it free. Even if you are not the original owner.