Krino Flat wood bits are fully hardened high performance drill bits with a centre point and a 1/4" hex shank. For use in wood and wood like materials and soft building materials. only. The winged shoulders enable the bit to first cut the wood and then remove the material from the centre section, ensuring a smooth finish and superior swarf clearance. This Krino flat wood drill bit comes in a handy plastic case and includes the following sizes: 10,12,16,18,20 and 25mm.