This Hole Saw Arbor has a 3/8 inch hex shank for greater gripping capability in the chuck. The backing plate is equipped with push pins which lock into holes on the backing plate of the hole saw for positive efficient transmission of torque. It can be used in 3/8″ capacity drills and larger. The arbor has a 5/8″-18 thread and can be used on hole saws from 1-1/4″ to 6″. Comes with 1 pilot bit.