The Starrett A2 Quick Hitch Arbor is engineered for compatibility with hole saws ranging from 32mm to 210mm. It features a durable design with a high-speed steel pilot drill and an 11mm (7/16") hex shank, making it suitable for a wide range of drilling applications. Brand: Starrett Suitable holesaw sizes: 32mm - 210mm (1.1/4" - 8.9/32") Pilot drill: 6.35mm (1/4") high-speed steel Shank: 11mm (7/16") hex shank Screw thread: 5/8" - 18 Quick Hitch feature: Allows for instant hole saw changes without tools or chuck removal Design feature: Set screw in the body allows for easy replacement of the pilot drill