Flat belt pulleys are used in transmission systems that are driven by flat belts, typically high-speed, low-power applications in textiles, paper making, and office machinery such as computer printers. Flat belts are also used for conveyors. Compared to plied belts of equal horsepower, flat belts are thinner by 25% or more, which allows flat belt pulleys to be smaller than V-belt pulleys. Flat belts are also less expensive than belts used in a serpentine belt pulley. One safety factor is that in overtorque situations, the belt can slip, preventing damage to equipment other than the belt itself. Flat belts require flat pulleys and flat pulley idlers. They do not necessarily require grooved flat belt pulleys. A flat pulley idler can also be used for the back side of a conventional V-belt. Flat belt drive pulleys apply motive power to the belt.