The RIDGID R4 (59502) Hole Saw Arbor with 1/2" Hex Shank is suitable for use with portable drills and drill presses. The arbor is easy to use, with no tools required for replacing a hole saw (not included). The R4 model is designed for 5/8 in. chucks and is equipped with a 1/2 in. Hex shank. The arbor fits saw numbers M76 to M152.