How to use a cordless multi drill bit fro Irwin is a remarkable insight into the way good trade supliers think. These drill bits are especially designed for cordless drills in that they take the need for a hammer acion to drill through normal masonry while coping with wood easily. They are very very sharp and can be bought from the DIY Doctor superstore at http://www.diydoctor.org.uk/DIY-superstore/drill-bit-set-for-cordless-machines-7-piece.html