Large Diameter: 3/8"Small Diameter: 3/16"Overall Length: 1-7/8"Cutting Edge Length: 3/16"Shank: 1/4"Keyhole Bits Are Used To Cut Keyhole Slots In Plaques, Picture Frames And Other Wall Hanging ItemsWide And Narrow Flute Design Requires Lower Feed Rates To Prevent BreakagePlunge Tip DesignMicrograin Carbide Tips Provide Superior Wear Resistance And Long Life