Diamond dressers are used to clean and sharpen grinding wheel edges by breaking away dull grains and smoothing surface grooves. Dressers can have one or more points. Single point diamond dressers have one diamond mounted to create a sharp point. Multiple point dressers contain multiple diamonds in a single or multi-layer configuration. These dressers are used for some roughing and finishing applications, but are not as versatile as single point dressers. Impregnated dressers have small diamond particles distributed in a matrix with a metal backing. They can be more effective for larger wheels.