This is the official U.S. military-issue tritium compass. It's been used by militaries, law enforcement and special forces (NSN 6605-01-196-6971). Made in the US by Cammenga, which has been the US government's exclusive manufacturer of this product since 1992. Features Include: Tritium luminosity, Sapphire jewel bearing, Bi-directional rotating bezel, Functions in -50 to +150 degrees, F Cast aluminum frame, Waterproof 10-year luminous, lifetime +/-0002mils accuracy Degrees & mils dial readings Induction damping process (no liquid required) OD Green Lanyard.