373212BX Boxed Bi-Metal Hole Saw - 2-1/2" (64 mm) Diameter. Variable depth gullets provide more efficient chip clearance. 4/6 Variable pitch teeth for reduced noise and improved performance. Electron beam weld for stronger, longer lasting teeth. Bi-metal construction for toughness and long life. Cutting Diameter: 2-1/2" (64 mm). Pipe Entrance: 2". Pipe Tap: NA. Material: Bi-Metal. Recommended RPM (In Steel): 135.