CMT 550-HW1 Carbide Tipped Center Drill with 5/16" Shank for Multipurpose Hole Saws 5/16-Inch hexagonal shank. Fits hole saws featuring a diameter from 25/32 to 1-3/16-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 Carbide tipped tool Total length 7-5/64-Inch