... in the design and manufacture of premium diamond drilling tools for the world engineering: geotechnical exploration, Mining exploration, Oil exploration ... PQ3, PWF-Long, PWF-Short6. S- Gauge Core Bits: SWF-Long, SWF-Short7. U- Gauge Core Bits: UWF-Long, UWF-Short8. Z ... φ130, φ160, φ170, φ219, φ27514. Chinese Standard Metric Core Bits for Double Tube Core Barrels: φ56, φ59, φ75, φ9115. Chinese Standard ...