Blu-Mol 7/16" Hex Shank Hole Saw Arbor in the original package. This is a quick change arbor, model #5545. This arbor includes a 1/4" high speed pilot drill. The arbor fits 1/2" and larger chuck drills. This arbor can be used with hole saws 1-1/4" - 6" with 5/8"-18 thread.