Ivy Classic  Bi-Metal Hole Saw              # DBXHS 27072 Is    4-1/2" Diam,Supports Heavy Duty Cutting With Its Rugged Construction, Which Is Constructed On Tough Metal. It Needs Just One Pass To Cut Through Studs. It Cuts Faster, Smoother Without As Much Vibration As The Others Due To Its Variable Pitch Teeth.  Uses pilot drill # 28136