... button bits, chisel bits, cross bits Model Number: X,XX,EX,EXX,EC,ECC,ESF ... The quality is stable.We can offer a large range of drill bits to suite the changing geology ... 20GrMo, 35GrMo, 40Gr. The products have the characteristics of small-sized, heavy-wall thickness, high precision, inner ... machinery. JYDR supplies precision tubes and a lot of spare parts for global incorporations.JYDR passed ...