Dual Arbor Kit provides two Hole Saw arbor mandrels that store in the space of one ordinary arbor • Use 5/8”-18 2-pin mount for hole saws 1-1/4” and larger ½”-20 adapter for smaller hole saw sizes • 7/16-inch hex shank for greater gripping capability in the chuck. Use with standard arbor extension • Comes with standard ¼” high speed steel pilot drill bit • For all hole saws from 5/8 inch to 7 inches in diameter