... surface, high efficiency, long life Diamond core drill bit with diamond particles evenly electroplated the surface, the core ... High Efficiency- Long Life Span- Environment FriendlySpecifications for core drill bits:Diameter: 4mm~120mmDiamond grit: #40 -#80, or ... marbles, granite, ceramic tiles, glass,cement,PVC,FRP,GRP,etcdiamond tools bitsdiamond core drill bitdiamond hole sawdiamond tools bitsdiamond ...