LENOX 1/2-in Steel Hole Saw Arbor in the Hole Saw Arbors department at Lowes.com
Milwaukee 49-56-9668 2-1/8 in. Hole Dozer Bi-Metal Hole Saw with 3/8 in. Arbor w/ pilot bit
Blue Boar Heavy Duty 7/16-inch shank Quick Change Dual Arbor Mandrel Kit for Hole Saws from 5/8” to 7” diameter, with both 5/8”-18 and 1/2”-20 thread mounts. - Hole Saw Sets - Amazon.com
Milwaukee Large Quick Change Arbor (ARMIL) - Custom Holesaw Technologies