They?ve been to battlefields all over the world. The Tritium Lensatic Compasses have proven themselves repeatedly in almost every kind of environment and situation. FEATURES: Equipped with 7 Tritium micro-lights Provides continuous illumination for over 12 years. Shockproof, damage-resistant design. Waterproof to considerable depths. Sandproof for extra durability. Accuracy +/- 40 mils.