40mm Tapered Bits, 40mm Chisel Bits, 40mm Drilling Bits manufacturer / supplier in China, offering 7 11 12 Degree Tapered Horse Drilling Bits for Rock Drilling Tunnelling, 7 Buttons Taper Tungsten Carbide Button Bits for Rock Drilling, 40mm Diameter 7 Teeth Tapered 7 11 12 Degree Button Bits for Marble Granite Drilling and so on.