BSS - Destinate Modl D3-T Tritium Protractr-CP Luminosity: Tritium (6 Sources). Jewel Bearing: Sapphire. Waterproof: Yes. Expected Luminous Life: 10 Years. Rotating Bezel: Bi-Directional. Optics: Map & Dial Magnifiers. Accuracy: +/- 40 mils. Resolution: 5 / 20 mils. Climate Capacity: -50 F to +150 F. Baseplate Materials: High-Impact Navalon.