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 sprocket. Martin MPC® Synchronous Sprocket, Solid Type AF-1, TB Bushed Bore, 1/2 to 2 in Bore Dia, 4.148 in Outside Dia, 4.211 in, 42 Grooves, 8 mm Pitch, 1-1/4 in Face Width, 4.91 in Flange Dia, 2012 Bushing, 1-1/4 in Overall Length, For Use With: 0.827 in W Belt, Steel