3/8" hex shank. 1/2", 20 thread. Standard pilot MLW49-56-8010. For hole saws 9/16" to 1-3/16" diameter This Milwaukee Hole Saw Arbor has a 3/8" hex shank for greater gripping capability in the chuck. It can be used in 3/8" capacity drills and larger. The arbor has a 1/2-20 thread and can be used on hole saws from 9/16" through 1-3/16". It can be used with 49-56-8010 pilot bit which is supplied with this Arbor for use on wood and metal. One arbor and pilot per package.