... are designed to drill the softest formations such as soft shales,red beds, and clays, with high durability and maximum ... with hard cherty streaks Model6-26( inch) TypeTricone bits, Steel tooth bits, PDC bits Applicable water well, oil field, ... Bearing rubber seal or metal seal Packing wooden box, steel box, or as your requirements Payment Term T/T ... , 537G, 617G, 627G, 637G API 8 1/2" steel cone bit