Mk Morse MHSA72/TA72 Real McCoy Bi-Metal Hole Saw, 4-1/2"Highlights: Diameter : 4 1 2" Variable pitch, 4 6 pitch Positive rake teeth reduce vibration and clear chips to improve cutting speed Attached pass through shank arbor is convenient and time saving Requires 4 5 16" pilot drill Positive rake teeth for more aggressive cutting action M3 high speed steel edge wire for toughness and excellent wear resistance Deeper gullets for better chip clearance Better tooth match for smoother cutting Modified 4 6 Raker