... 3.Three kinds of faces design 4.Longer service life DTH Hammer and Bits1. Deliver maximum energy to drilling bit, ... theory.2. Smooth performance and long service life of GM series DTH hammer due to high quality alloy steel materialsand ... SD8QL40,QL50,QL60,QL80CIR65,CIR80,CIR90,CIR110COPROD89,COPROD102,COPROD127 Hammer typeBitsFace designAPI threadDiameterWork pressureG24(2")76/80mmFlat/Concave/ConvexF42 ...