Holds up to 50 times longer than a bi-metal hole saw in tough materials. Most hole saws for wood and metal seem to work well until you hit a hardened nail or screw. Then they scream, smoke, and grind until the teeth are ripped out, and the hole is still not finished. With its carbide teeth, the Expert Tough Material hardly slows down when it encounters metal. It cuts cleanly through the material and does so reliably. Each tooth made with Bosch Carbide Technology has optimal quality from the hardest metal. It is laser-welded and ground six times to achieve the perfect cutting shape. This makes the Bosch Expert Tough Material hole saw ideal for heavy-duty tasks and versatile work: in addition to wood and metal, the hole saw is also well-suited for stainless steel, brick, soft tiles, and reinforced plastics. The Bosch Expert Tough Material hole saw is an excellent all-rounder for any craftsman, as no one can make use of just a half hole. Designed for use with Bosch's Power Change Plus quick-change adapter: for precision and durability. Diameter mm: 64, Diameter inches: 2 1/2, Working length mm: 60.