Hole Saw Arbor, Manufacturer suggested retail price. $7.50 Feature and Benefits: 1/4 in. round shank 1/2 in. - 20 thread Standard pilot 49-56-8000 For hole saws 9/16 in. to 1-3/16 in. diameter This Milwaukee hole saw arbor has a 1/4 inch round shank and can be used in 1/4 inch capacity drills and larger. 49-56-6950 for use on wood or metal. One arbor and pilot bit per package. Manufacturer: Milwaukee Electric Tools 5 yr warranty on material and workmanship