Tusk HRS drill bits, made from M2 high-speed steel also have a titanium nitride coating for longer life. Their 135-degree tip offers a faster drilling rate and lower feed pressure. The self-centring ‘split point’ is designed for easy piloting and precise drilling. Suitable for steel, soft stainless and soft cast iron, aluminium, copper, brass, bronze, and hard plastics they are are available in 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5mm drill diameters with reduced shanks to fit 10mm or 13mm chucks. They are also available in 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20, 20.5, 21, 21.5, 22, 22.5, 23, 23.5, 24, 24.5, 25, 26, 27, 28, 29, 30, 32mm diameters to fit 13mm chucks.
For more info http://www.tusktools.co.nz/drilling.html