... experience, now Zhongrui can manufacturer the best quality DTH rock drill bits, DTH hammer and chisel bit, thread button bit. ... we can supply 90mm-254mm(3.5"-10") DTH rock drill bits, 340,350,360,380, COP44, COP54, COP64, COP84 , ... face4.73-1319ZL5ZRQ110ZRC100Z6-1319QL7-1422QLConvex face5.86High pneumatic DTH drill bitZRQ115G-AZRC100GZRC100G-ADHD340COP446-1319Q8-1422QFlat face8.27ZRQ115G-AZ6-1319Z8 ...