... , COP model 4"-8" quick hammer High drilling rate Low air consumption Quality products good ... Zhongrui can manufacturer the best qualith DTH drill bit, DTH hammer. Now we can supply 90mm-254mm(3.5"-10") ... DTH hammer, 340,350,360,380, COP44, COP54, COP64, COP84 , 3"- ... ,350,360,380 4",5",6",8" quick hammer with very good price and service. No.ModelOutside diameterLength ...