... B10# ——applicable to stable,vitreous,weak abrasive stratum.C series----made of large grain diamond,supper high crown(grey)C series ... is uncertain.C7#,C8# ——applicable to stable,vitreous,low abrasive,hard and slippery stratum.C9#,C10# ——applicable to stable, ... vitreous,weak abrasive stratum.Standards:To cooperate with Q series drilling tools,bits ...