Features and Benefits: Available in 6" and 12" lengthsNot for use with quick change woodboring bitsAdds 12 inches to regular bit length and follows 5/8" or larger bit through the holeForged of high quality tool steel and made in heavy-duty, double set screw typeFor fast, rough or clean and exact holes, IRWIN's extensive line of woodboring drill bits provide the user with the best available tools for each application in achieving their wood drilling needs. Available in 2 in.; in.;, 6 in.; in.; and 12 in.; in.; lengths, the bit extensions give the user additional length for hard-to-reach areas. Available in 6 in.; in.; and 12 in.; in.; lengths. Not for use with quick change woodboring bits.