... steel Certificated by API&ISO9001:2008 8 1/2" New PDC Bits for Well Drilling Description about sell rock bits,tricone bits ... in the field of mine, transportation, tunnel and hydroelectric for shelving reticular support.Model114,117,127,437,517,617,637 ... TypeTricone bits, Steel tooth bits, PDC bits Applicable water well, oil field, construction, geothermal, directional boring, and underground ...