Irwin Blue Groove 6X Stubby Wood Bits are ideal for drilling wood and offer 6 times faster drilling penetration than a standard flat bit. Their 'Tri-Flute' design allows for faster chip ejection and their full screw tips ensure ease of use and pull through. The cutting spurs produce clean holes with minimal breakout and the tapered flute reduces binding. The drill bits are also heat treated for extra durability. Stubby drill bits are 10cm (4in) long, making them ideal for drilling through joists or in enclosed areas. Suitable for holes up to 5cm (2in) deep.5 Piece Stubby 6X Blue Groove Wood Bit Set comes with a free extension is supplied with the following sizes: 16, 18, 20, 22 & 25mm.Additional Information:• Overall Length (mm): 100• Working Length (mm): 50• Pack Qty.: 5