... 3. No noise, high efficiency NOVO's timing pulley:1. Plain bore: MXL, XL, L, H; T2.5, T5, T10; AT5 ... , Zinc Plating, Hard anodized, Nitriding, Dichromate.5. Teeth Number is from 9 to 216.Specifications1.high quality and most competitive in ... qualityCertification:We've been ISO9001:2000 certified since 2003. HTD plain bore pulleys