Take the guesswork out of measuring bicycle components and parts with Feedback Sports' excellent Digital Caliper. This precision stainless-steel digital vernier caliper boasts a large LCD screen that displays outside and inside measurements up to 6 inches (150mm) and down to 0.0005 inch/0.01mm. You can measure seatpost diameters, bottom brackets, stem lengths and more with this highly accurate tool and easily switch from inches to mm. You can also zero the setting in any position. There's even a handy dimension look-up chart for bicycles on the back. This fine tool runs on a 1.55-volt battery that's included, has an auto shut-off to save the battery and comes with a protective carrying case and a 1-year warranty.