This is Aluminum GT2 Timing Pulley 20 Tooth 6.35mm Bore For 6mm Belt. For precise motion control, GT2 belts and pulleys offer excellent precision at a great price. This pulley is meant for use with GT2 6mm wide belts only – MXL belts will slip due to the different tooth profile.
This pulley has 20 teeth and a 6.35mm inner bore. Two set screws can be used to attach it firmly to any 6.35mm diameter shaft. Full aluminum construction means these are very light and very durable.