Martin timing pulleys 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 Stock Timing Pulley, Solid Type DF-1, Minimum Plain/Reborable Bore, 1/4 to 1/2 in Bore Dia, 0.999 in Outside Dia, 1.019 in, 16 Grooves, 0.2 in Pitch, 0.563 in Face Width, 1.248 in Flange Dia, 11/16 in Hub Dia, 7/32 in Hub Projection, 25/32 in Overall Length, For Use With: Type XL Belt, Steel