This Girdle Calibration machine for Gemstones is equipped with a motor and is used to calibrate the girdle of a gemstone to a specific size. This is a manual machine and uses a Diamond Wheel of 6" diameter and 1/2" width. You can choose different grit sizes of wheels for different stones. The stone is held through a vise with Nylon bushes to avoid any damage to the stones. The vise is designed that the stone is automatically centered against the wheel.