high quality best price ,delivery on time. all IADC code. Certified by API. With API and ISO9001 2 High quality and competitive price 3 Size: 8 1/2inches, 9 1/2inches, 12 1/4inches or according to your request.4 Fast drilling rate Be used for water well, oil field, underground, construction, geothermal, directional boringImproved support and retention, diamond are impregnated in the matrix behind ...