... & dimension available 5-High speed Steel tooth Tricone drill bit Hejian Fist Petroleum Equipment Co., Ltd. We ... formations(114-117)These bits are designed to drill the softest formations such as soft shales,red ... ,134,136,137)These bits are designed to drill formations such as shales, medium soft limestone, ... ,214,215,217)These bits are designed to drill formations such as hard sandstone, dolomite, and ...