Speed reducers, also called a gearboxes and gearheads, as well as gear reducers etc., consist of a set of gears, shafts and bearings that are factory mounted in an enclosed lubricated housing. Speed reducers are available in a broad range of sizes, capacities and speed ratios. Their job is to convert the input provided by a prime mover (usually an electric motor) into an output of lower RPM and correspondingly higher torque.