3"-8" dth hammer DHD, COP model 4"-8" quick hammer High drilling rate Low air consumption Quality ... , 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 ...