These sprockets have been machined from solid polyamide material. Therefore giving them a completely closed structure which is easier to clean and disinfect. The reinforced design of the sprocket ensures smooth running with reduced noise levels. Additional benefits include increased keyway strength, excellent chemical resistance and long service life. System Plast™ Machined Return Idler Sprocket, Heavy Duty Single Strand Split, 1-1/4 in Bore Dia, 6-1/2 in Outside Dia, 1700/1701 TAB Chain, 10 Teeth, 6.37 in, 4.33 in Hub Dia, 3/8 x 3/16 in Keyway, 1.77 in Length Through Bore, Reinforced Polyamide