This Milwaukee hole saw arbor has a 3/8 in. hex shank for greater gripping capability in the chuck. It can be used in 3/8 in. capacity drills and larger. The arbor has a 1/2 - 20 thread and can be used on hole saws from 9/16 in. to 1-3/16 in. it can be used with 49-56-8010 pilot bit which is supplied with this arbor for use on wood and metal.