The Spyder auger drill bit set contains 3 sizes, 1/2 inch, 3/4 inch, 1 inch and are compatible with Irwin models. The stinger line of auger bits is fitted with a unique double twist fluting that vibrates less and produces less friction than traditional single and triple twist auger bits, making the new Spyder products among the easiest-to-control in deep boring applications. The dual cutting edges score the outside of the wood while simultaneously clearing excess material from the work surface creating extremely clean entry and exit holes with optimal chip flow. Spyder has also hardened the cutting edge allowing for users to power through nail embedded wood. The 7/16 inch and 3/8 inch no-slip hexes are impact rated for use in battery powered quick change tools. Unlike other auger bits with a self-feeding thread point, the Spyder stinger thread point will not clog and will not wander-making you more productive. Hardened cutting edges power through nail embedded wood. Impact rated for use in battery powered impacting tools.