Kreg Jig? HD Screws are optimized for use with the Kreg Jig? HD and 11/2″ and larger stock. These large 21/2″-long #14 hardened-steel screws provide incredible shear-resistance and have a Protec-Kote? finish with three anti-corrosion layers for long-term moisture resistance in damp or wet applications. #3 square driver. Will work in treated lumber.