... ISO9001&API2)Fast drilling rate3)Strong cutting structure durability4)be used for water well, oil field, underground, construction, geothermal, ... directional boring5)Be used to drill low compressive strength,soft formation6)various of model ... rods,drill collar,rerun steel tooth bits, ,used drill bits stock,used mud pumps,etc Model 114-117,127,437,517,617 ...