Leupold Quick Release Two Piece Base BAR Matte Black, The QR Mount promises repeatable accuracy. Super-close machining tolerances are at the heart of this patented lever mechanism. By turning the lever forward, an eccentric on the lever shaft engages the base of the ring. This pulls the ring down and forward on the base, locking it solidly into its "zero" position. , Mfg No: 51223, Manufacturer: Leupold, : Full lifetime . 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.