7/16" Hex Hole Saw Arbor Shank with Flat Shank Milwaukee hole saw arbors are made from hardened carbon steel and alloy steel for greater durability. The 49-56-7000 features a 7/16" Hex shank, which can be used with any 7/16" Extension. Features: 7/16" Shank 3-Flat Shank Up to 1-3/16" Since its founding in 1924, Milwaukee has focused on a single vision: To produce the best heavy-duty electric power tools and accessories available to the professional user. Today, the Milwaukee name stands for the highest quality, durable and reliable professional tools money can buy.