The Merit Lighting PERMEX P-180 series incorporates virtually fail-proof tritium/phosphor technology. The system has been used for years in aviation and also in military and manned space applications where reliability is absolutely essential.
Each light source is internally coated with phosphor (ZnS) and filled with tritium (H3) gas. As the gas decays into helium, low energy beta particles are produced which strike the phosphor causing it to luminesce.
The P-180 Series is U.L listed and conforms to U.L. Standard 924