... 3M,5M,8M,14M Types:T2.5,T5,T10,T20 Bore types: SB,TB,QD Timing pullyBritish Types: MXL,XL,L,H ... ,20M AND SO ON2. Metric System: T-type series(T2.5,T5,T10,T20)3. HTD type(3M,5M,8M,14M ... .5M,S5M,S8M,S14M)5. The British System:MXL,XL,L,H,X6. Material:1045 carbon steel, aluminum alloy frequently used,brass ... -plating8. Tolerance:conform to customers requirement9. OEM/ODM service:offered Aluminum timing pulley