Ivy Classic, 27040, 2-1/2", One Piece Bi-Metal Hole Saw, Cobalt Advantedge blades are designed for heavy-duty cutting in most machinable materials including, stainless and mild steels, non-ferrous metals, plastic and wood. Convenient, one-piece hole saws save arbor changes. Bi-Metal construction with M-3 cutting edge. Variable pitch, positive rake tooth design (4 - 6 TPI). 1-1/2" cutting depth cuts through 2x4s. Solid alloy steel back reduces vibration.