Milwaukee 48-28-4001 5-1/2-Inch Hex Shank Extensions for Selfeed Bits, Auger Bits and Hole Saws Over 1 The product is easy to use The product is durable The product is manufactured in China features a hex-shaped shank that delivers more torque and won't spin in the chuck For self-feed bits, auger bits and hole saws (1 inch diameter and larger) Designed to fit Milwaukee Selfeed Bits, Auger Bits, and Hole Saws, 3-jawed chucks, and 7/16-inch Quick Change chucks