Impregdiamond diamond core bits 1.For mining and geological exploration 2.Fast drilling, Low pressure , Long life Impregnated ... a tungsten carbide matrix.3, Fast penetration rate , best recovery and long life. 4, Item Size: HQ, NQ, BQ, AQ, FQ ... , T series, etc5, Item Package: Cartons and Pallets NQ HQ BQ impregnated diamond core bits