... ,HTD:3M,5M,8M,14M,20M AND SO ON2. Metric System: T-type series(T2.5,T5,T10,T20)3. HTD ... (S2M,S3M,S4.5M,S5M,S8M,S14M)5. The British System:MXL,XL,L,H,X6. Material:1045 carbon steel, aluminum ... :conform to customers requirement9. OEM/ODM service:offered Aluminum timing pulley