The Fail-Safe EXL offers buyers one of the best high-abuse, specification-grade exit signs on the market. Its architectural low profile combines 14-gauge steel and a 1 - 8-inch polycarbonate lens to withstand the toughest environments. The door attaches to the housing with four tamperproof fasteners. LEDs power the unit for energy-efficient, even illumination. These fixtures are UL - cUL listed for damp locations. The EXL is specifically designed for use in public access areas where safety and security are critical; it is ideal for use in maximum security correctional facilities, public housing, schools, psychiatric wards, detention centers, military barracks, parks, and hospitals.