A few Victorinox Swiss Army knives include a digital altimeter that runs off a
small lithium battery. The altimeter shows the current elevation in both feet and meters, for any elevation from -300 feet (-100 meters) to +18,000
feet (6,000 meters). You can adjust it easily to compensate for temperature and barometric pressure.
The altimeter also shows the temperature in degrees Celsius and Farenheit (range 0° to 140° F, or -20° to 60° C).