The 1779803 Lenox Tools 4L Arbor fits Lenox Hole Saws from 9/16 inch to 1-3/16 inch, (Sizes 9L thru 19L). It features a 3-Flat Shank sized for use with 1/4” and larger drill chucks. The 4L Arbor includes a 1/4” pilot bit and will also work with most compatible brands of hole saws. The 4L Arbor is a screw-on style arbor and a hole saw is mounted simply by screwing it on tight to the arbor. The pilot bit is secured by a set screw and is easily removed and replaced, (part # 1779771), using an 1/8” Allen drive hex key, (hex key not included).