Helps prevent dinged and damaged scope tubes by removing high spots to quickly true misaligned or out-of-round scope rings so they're perfectly in line. Also works to turn-in and rough align rotary dovetail rings. Dual-handles with multiple, transverse, lapping compound grooves give complete control and fast results. Includes lapping compound. Mfg: Brownells SPECS: Mild steel, in-the-white. 12" (30cm) long, 1" (2.5cm) or 30mm (1.187") dia. Includes (2) plastic handles and instructions.