7/16″ x 12″ Hex shank extension for self feed saw tooth bits, auger bits and hole saws. extends your reach a full 12″ inches. Fits three-jawed chucks, 1/2″ drill chucks larger. Also fits 7/16″ quick change chucks. We also have this in 5-1/2″, 18″ and 24″ lengths. Call us today 1-800-350-8665 Ext: 100