... design and manufacture of premium diamond drilling tools for the world engineering: geotechnical exploration, Mining exploration, Oil exploration and hydrapower ... reaming shells, overshot, hoisting plug, water swiel, wrench. 1.Drill rod: BQ, NQ , HQ, PQ, NT, HT Casing tube: BW, NW, HW, ... HWT, 2.Core barrel: BQ NQ NQ2 NQ3 HQ HQ3 PQ PQ3 head assembly and assemblies 3.AQ,BQ,NQ,HQ,PQ, BTW, NTW, T2, ...