... 3.Type:Trapezoid tooth,T synchronization ,HTD(STD)synchronization Timing Belt Pully Specification:Trapezoid tooth MXL,XL,L,H,XH,XXH ... the cost is low 2.Accurate and constant ratio, can work without sliding 3.It's stable, low noise 4.High ... transmission efficiency, save energy obviously 5.No pollution, can work properly in bad working environment If you need more information ...