The Inchworm is a functional keychain accessory that you'll use more times than you ever thought. A "ruler in the round", the Inchworm is a rod of 3/16" diameter 6Al-4V grade titanium with grooves cut at 1/8" increments up to 3" long. The outside surface is bead blasted to a uniform matte finish, and new grooves are then cut at the 1/2" marks and 1" marks for ease of reading. Use it to check your tire tread depth, check the width of your broken fan belt, measure hardware lengths, or calculate distance on a map.