A cluster of genuine diamonds is mounted in a holder and used to dress or open the grindstone when the stone becomes grooved or glazed. It takes only a few seconds to set up and can really improve the performance of the wheel. Dual knob screw permits an easily controlled feed across the stone for a perfect flat surface. If you feed faster, you can create a rougher surface which grinds more quickly. Mounts and locks instantly in the right position on the Universal Support of the TORMEK Sharpening System. The cutting depth is controlled by the Micro Adjust on the Universal Support. If you have an older machine without Micro Adjust it can be retrofitted by ordering the US-105.