Self-luminous, independent operation exit sign. Illumination provided by borosilicate glass tubes, internally coated with zinc sulphide phosphor and filled with tritium gas. Minimum brightness at time of manufacture is 0.132 foot-lambert (0.452 cd/m2). Decorative, slim-line heavy-duty ABS housing. Rugged, impact-resistant polycarbonate face. Spark free construction. Simple installation - universal direction capability, comes complete with universal mounting hardware. Stands up to extreme temperatures in outdoor or indoor applications. Standard 12-year life expectancy. 15-year life expectancies available as an option.