... in the design and manufacture of premium diamond drilling tools for the world engineering: geotechnical exploration, Mining exploration, Oil ... AQ-PQ) and assemblies, synthetic diamond core bits, natural diamond surface-set core bit, PDC bits (core or noncoring), casing shoes, reaming ... , reaming shell & shoe bit (syn. and surface-set, PDC)4.Drill tool: hoisting plug, water swivel, overshot (standard, ...