$54.99 Bosch 2-1/2 in. Bi-Metal Hole Saw Drill Bit-HB250 - The Home Depot
Koopi 3-1/2 BI-METAL Hole Saw with Arbor and Replacement Pilot Drill Bit, 89mm Diameter Hole 
Lenox 1779774 Hole Saw Arbor With Pilot Drill Bit; 1/2 Inch Larger, Hollow Hex Shank, 1/2-20 
