A belt conveyor consists of two or more pulleys, with a continuous loop of material, the conveyor belt which rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the non powered pulley is called the idler. There are two main industrial classes of belt conveyors; Those handling such as those moving boxes along inside a factory and bulk material handling such as those used to transport industrial and agricultural materials. Generally in outdoor locations. Generally companies providing general material handling type belt conveyors do not provide the conveyors for bulk material handling. In addition there are a number of commercial applications for belt conveyors such as those in grocery stores.