All Traser H3 watches feature trigalight technology (Gaseous Tritium Light Sources - GTLS) this is the same technology used by other leading manufacturers such as Marathon, MWC and Luminox, these type of watches are easiest watches in the world to read in low light or even total darkness. This technology does not require a battery or external power source in order to work and never needs recharging or servicing. Guaranteed for 10 years, this technology fitted to the dial and hands of all Traser H3 watches makes them ideal for military and emergency services personnel as well as the outdoor adventure enthusiasts.