The Diamondhead USA Non-coring Core Bit (Turbo Core bit) 

Diamondhead USA Non-Coring Core Bit can be used on all types of porcelain and ceramic tiles either dry or wet. They are able to withstand the toughest working conditions and are widely used in the North American market. They are available in sizes 3/16 inch, 1/4 inch, 3/8 inch and 1/2 inch of 5/8-11 thread