... 5-10 times longer than diamond plated bur For dental lab,jewelry,lapidary,gemstone 5 grits. Technology:1. Consist of diamonds ... marked with color ring for reference of grit Color ringGritDental lab usageLapidary / jewelry / gem usageBlack Super coarse70meshISO 544Fast aggressive on porcelain ... items for select HP shank 320 mesh fine grit dental lab sintered diamomd carving tools for gemstone