The Waltham Wrist Compass had a brass case and a one-piece nylon strap. The compass points and needle were illuminated by radioactive vials, which depleted after several years. It was issued to a few thousand infantrymen late in the Vietnam War1 and was a component of the leg holster survival kit. However, like the Lensatic Compass, it was not waterproof.1. Jungle Snafus...and Remedies by Cresson H. Kearny (Oregon Institute Of Science And Medicine 1996)