3"-8" dth hammer DHD, COP model 4"-8" quick hammer High drilling rate Low air consumption Quality products good price With yeas of experience, now 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"-8" DTH hammer, 340,350,360,380 4",5",6",8" quick hammer with very good price and ...