... due to the special innerstructure of GM series DTH hammer designed according to newest rock drilling theory.2. ... 115mm 120mm, 127mm, 133mm, 140mm, 146mm, 152mm, 165mm, 175mm,190mm, 203mm, 216mm 254mm, 305mm, 330mm, etc.Mission 30,Mission40, ... SD8QL40,QL50,QL60,QL80CIR65,CIR80,CIR90,CIR110COPROD89,COPROD102,COPROD127 Hammer typeBitsFace designAPI threadDiameterWork pressureG24(2")76/80mmFlat/Concave/ ...