The Forney 20561 aircraft extension drill bit, 1/16" x 6" Industrial Pro high speed steel (HSS) fractional aircraft extension drill bit with 135-degree split point that allows the cutting action to begin immediately, penetrate faster with less pressure and prevent walking. Aircraft extension drills are normally operated in portable electric drills and are used for drilling holes in hard-to-reach places. They are used in aircraft plants for wing and tail assemblies and for drilling cowlings, spars and firewalls. No center punch is needed. National Aerospace Standard 907, Type B, aircraft extension drills Type A243. Forney Industries is one of America"s longest operating family-owned metal working product companies. Founded in 1932, Forney offers more than 5,000 products for the hardware, automotive, farm & ranch and do-it-yourself markets. If you"ve got metal working questions, we"ve got answers. Were committed to your success regardless of location size or needs. 1/16-inch-by-6-inch (1.59mm x 15.24cm) aircraft extension drill bit. Claims for warranty must be made within 90 days of the date of purchase. Proof of purchase required. This warranty does not cover any product that has been subject to misuse, neglect, negligence or accident, or that has been used in any way contrary to the purpose intended.