Cleaning out my father's estate and I have no idea how to test this.  Looks like it's in good condition.

This vintage Wallace and Tiernan Portable Altimeter is a must-have for any collector of WWII memorabilia. Made in the United States and formerly used by the US Military, this altimeter is a piece of history that you can own. Its compact size makes it easy to display or store, and its functionality as an altimeter adds a unique touch to any collection.

The altimeter is in great condition and has been well-maintained over the years. It is an excellent addition to any collection of engineering or surveying equipment. Don't miss out on the opportunity to own a piece of history.