Type: button bits, chisel bits, cross bits Model Number: X,XX,EX,EXX,EC,ECC,ESF ... is stable.We can offer a large range of drill bits to suite the changing geology encountered durig project, the ... 160Mn, 20GrMo, 35GrMo, 40Gr. The products have the characteristics of small-sized, heavy-wall thickness, high precision, inner or outer special ... customers for Win-Win businesses. DingRun High Quality Drill Bits