The Kestrel 4000 and 4200 Series Pocket Weather Trackers don't just measure every environmental parameter you need to consider for racing, it also tracks and stores 480 measurement points for each parameter. This means you can view what has happened in the past, as well as predict what's ahead. You can even upload the information to your computer for use with dozens of applications. On-the-spot density altitude calculation makes the Kestrel 4000 a necessity for drag racers dialing in their cars. A storage pouch, wrist/neck lanyards, and batteries are included.