BALL watches feature self-powered micro gas lights containing tritium 3H for the ultimate in night readability. Gaseous tritium light sources GTLS glow 100 times brighter than luminous paint for more than 25 years! BALL exclusively uses GTLS that are certified for military use. Other BALL Watch innovations are a 7,500 G force shock resistance, the -40 degree Celsius temperature rating, a mechanical thermometer complication, and a patented crown protection system.