... proof2)Serface treatment - Chrome, Special honing, blast sanding, Phosphating, or we can make it as customers' request.3) Material- KV1, K1 ... Keystone, 2nd ring Taper faced, 3rd ring DSF, or we can produce as customer's request.5)Quality certificate- ISO9001 ... quality with competitive price. Secure service, deliver on time. We are your reliable cooperation partner.CUMMINS other models:6BT.6CT,NT855,K19 ...