An overlay trimmer resembles a little switch. It is a light, one-hand device, controlled by little (3–4 amp) engine, that is exceptionally intended for trimming overlay. The bit paints the town bearing that moves along the surface while the cutter cuts the edge off. A common cover trimmer is furnished with a 1/4-inch collet. The engine keeps running in the 20,000–30,000 rpm go – speedier than most switches to make up for the way that the bits are littler in breadth.