The Armor Color-Coat pocket screws are the perfect fastener for any project. A color-coded system differentiates screw length and matches it to the exact material thickness shown on the self-adjusting guide block, providing you the strongest pocket hole joint possible. The Color Coating also assists in reducing corrosion, making it a good choice when building outdoor projects. Simply place your workpiece into the Auto-Jig, clamp, and match the indicated color on your guide block to the screw color. This will give you the optimal screw length for your project. (Projects utilizing different thickness material will refer to the user manual for the correct match length). Screws come in coarse (for soft woods) and fine (for hard woods) threads, with lengths of 1″, 1 1/4″, 1 1/2″, 2″, and 2 1/2″.