Classic military styling-this is the watch issued to UK Special Forces. Revolutionary Gaseous Tritium Light Source (GTLS) Technology produces bright illumination that keeps its brilliance for ten years or more, and it's always on-doesn't require "charging" from an external light source. The MX10 has an armor-hard exterior, triple-coated sapphire crystal, and polymer band with double-toothed stainless steel buckle. Triple O-ring sealed and waterproof to 330 ft.