... , NQ2, HQ3, PQ3 T2, T6, LTK NMLC, HMLC, NX BW, NW, HW, PW, NWT, HWF Specialisted in producing varies kinds of ... , chert, abrasive rock etc. Including impregnated diamond core bit, surface-set diamond bit, reaming shells, casing bit, casing shoe bit, corelifter, corelifter case, core ...