U.S. federal trademark · Serial No. 85189803 · Reg. No. 4712688
A coring tool for drilling comprising a two piece fixed cutter drill bit and an interchangeable doughnut hole, the doughnut hole portion of the bit being interchangeable with a wireline retrievable core barrel
Source: USPTO federal trademark records. Informational only, not legal advice. Status and details may lag the live USPTO database.