... ,material:C45 or Q235 2,our chain coupling is standard 3,all stock coupling is harden teeth chain couplingnew star industrial sprocket ... in industrial sprocket and industrial gear,gear rack, flange and coupling. our products are popular in Africa,South America,USA,Mid ... standards, AGMA standards2.Material can be C45, 40Cr, 20CrMnTi, 42CrMo, copper, stainless steel and so on as per your request3.There ...