... 4.inner diameter:12mm 5.pitch:12.70 Specificationsindustrial transmission roller chain sprocket MaterialC45,40Cr,20CrMnTi,42CrMo,stainless steel ..... as per your ... and triple)05B,06B,08A,08B,10A,12A,16A,20A,24A,28A,32A,40APayment,minimum order and deliveryT/T (30% deposit ... -win business relations with you in the near future. industrial roller chain sprocket