Milwaukee hole saw arbors are made from hardened carbon steel and alloy steel for greater durability. The 49-56-9100 features a 7/16 inch hex shank, which can be used with any 7/16 inch extension. The 49-56-9100 also features a drive plate which is tightened up to the hole saw to eliminate wobble between the arbor and hole saw. What's Included: (1) Large Thread Quick Change Arbor, 7/16" Shank (49-56-9100)Tool-free operationUniversal, quick change with all brands of hole sawsNo adapters requiredDurable hardened steel constructionFits all hole saws 1-1/4 in. and largerFits all drill chucks 1/2 in. and larger