The Irwin Speedhammer Plus Drill Bits are designed for exceptional fast drilling in brick, block, masonry, concrete & granite. The patented, unique single flute design ensures efficient, speedy removal of dust & lower vibrations & 28% greater capacity meaning more efficient waste removal. They have a patented extra short drill bit head which means the head takes 80% of the workload, ensuring higher durability & speed. Clears drilling dust directly into the flute, reducing the risk of clogging. The bits have 25% more tungsten carbide for extra strength & they drill 25% faster than competitive drill bits with the same high durability. In addition, they have more aggressive cutting angles & self-centring for faster drilling. The Irwin IRW10501976 Speedhammer Plus drill bit has the following dimensions: Drillbit diameter: 9.0mm Total length: 210mm Working Length: 150mm