... compact) grades and shapes applied for rock formations as follows:1. Andesite, marble, metamorphic schist (For hard, low abrasive formations) ... ,617,637 TypeTricone bits, Steel tooth bits, PDC bits Applicable water well, oil field, construction, geothermal, directional boring, and underground ... Payment Term T/T or L/C at sight MOQ 1 Piece Supply Ability 1000 Pieces/month Delivery Time within 7 work ...