Products Included: 6-Piece Core Drill bits(20/35/40/45/50/68mm)total 6 pieces/Box Easy to use,Thread size is 9/16-Inch(14mm) which apply to angle grinders with 14mm(9/16-Inch) connecting shaft,Can also be used for hand drills after installing the connecting shaft Core Drill Bits are designed for Dry/wet drilling porcelain tile, granite, marble, brick and all similar material Vacuum Brazed technology provide much longer working life,fast and smooth drilling These drill bit kit is suitable for both dry and wet use. To prolong the life span, it is recommended to used with water for cooling and lubrication Diamond Core Drill Bits Set - 6pcs Tile Hole Saw Kit 20/35/40/45/50/68mm with for Porcelain Ceramic Tile Granite Marble concrete Glass