The Drill Rite precision drill guide is an easy, accurate way to drill any curved surface or tubing from 1/2" to 2-1/2" in diameter. Light and portable, it produces straight and true holes every time. Includes super hardened drill bushings for popular 3/16" and 1/4" holes for rivets and aircraft hardware. Additional bushings are available for most hole sizes. Made in U.S.A. from aircraft grade aluminum.