... chert, firm sandstone, and firm anhydrite and so on.4.According to your request, all sorts of products can ... .5mm(6 1/8”),158.7mm(6 1/4”),161.9mm(6 3/8”),165.1mm(6 ... 2(13 3/4”)374.6(14 3/4”)381(15”),393.7(15 1/2”),406.4(16”)444.5( ... 17 1/2”),508(20”),558(22”),609.6(24”)660.4(26”) Steel ... L/C at sight, western unionProducts show 8 3/4" IADC 527 Kingdream drill bits for rocks HAS series ...