Irwin Power Drill I-100 Auger Bit Sets Solid center design provides extra rigidity while boring. The flutes are ground behind the lands to funnel chips to the inside of the bit and away from the outside diameter, producing a faster, cleaner . Wide lands keep the bit straight as it bores through the hole. Coarse screw point provides fast boring in hard and soft woods. All bits have a 4-1/2" twist length and a 7-1/2" overall length Pack of 1