... X,XX,EX,EXX,EC,ECC,ESF,ESSF,ESD,ESSD,EY,EYY DingRun High Quality Drill Bits1) ... X,XX,EX,EXX,EC,ECC,ESF,ESSF,ESD,ESSD,EY,EYY Self-drilling Anchor Drill BitSpecification ... engagement in R&D, manufacturing and international trade of precision steel tubes, and has more than 3500 ... 160Mn, 20GrMo, 35GrMo, 40Gr. The products have the characteristics of small-sized, heavy-wall thickness, high precision, inner or ...