The VIT102795 Hard Tile Drillbit has the following specifications:
Diameter: 15mm.

The Vitrex Diamond Grit Edged Drill Bits are ideal for drilling hard tiles. The slotted bit design makes for easy waste removal.

It is suitable for drilling porcelain, granite, quarry, stone, marble, terracotta and ceramic tiles.

For use in conjunction with: -

VIT102788 - Universal Hard Tile Drill Bit Guide
VIT102790 - Water Cooling System