Martin MPC® sprockets are manufactured to extremely close specifications and are stocked in minimum plain bore, taper bushed, QD Bushed styles depending on size and pitch. Synchronous sprockets are non-slip toothed drives that require no lubrication. These sprockets have a wide speed range are very efficient and make less noise than chain drives. Teeth on the belts are molded to conform with and engage the teeth on a mating pulley. Martin MPC® High Torque Belt Drive Sprocket, Solid Type AF-1, TB Bushed Bore, 1/2 to 2-1/2 in Bore Dia, 5.329 in Outside Dia, 5.439 in, 31 Grooves, 14 mm Pitch, 3.33 in Face Width, 6.11 in Flange Dia, 2517 Bushing, 3.322 in Overall Length, For Use With: Polychain GT2® Belts and Falcon Pd® Belts, Steel, Protective Coating