CMT 550-HS2 Steel Center Drill with 25/64" Shank for Multipurpose Hole Saws 25/64-Inch hexagonal shank. Fits hole saws featuring a diameter from 1-1/4 to 6-Inch Drill is easily fastened into the hole saw and is easily removed thanks to our innovative patented system No additional tools needed to remove the drill Made of HSS steel Total length 7-5/64-Inch