... , and specializing in the design and manufacture of premium diamond drilling tools for the world engineering: geotechnical exploration, Mining exploration, ... bit, PDC bits (core or noncoring), casing shoes, reaming shells, overshot, hoisting plug, water swiel, wrench. 1. Drill rod: BQ, ... -set, PDC)4. Drill tool: hoisting plug, water swivel, overshot, outer tube & inner tube wrench, foot clamp,etc.