The SR series LED exit sign with power pack's housing and faceplates are constructed of steel. The exit sign shall have a maximum depth of 2-1/2 in. The faceplate(s) are supplied with standard knockout chevrons and the light source for the unit is light emitting diodes (LED). The LED lamps provide illumination in normal and emergency operation and shall be mounted inside the exit housing, not on the face. The power pack is a completely self-contained emergency unit with its own charger and rechargeable battery. When a power failure occurs, the exit sign and the emergency heads shall illuminate in emergency mode for a minimum of 30 min. The power pack shall include a test switch and a high charge pilot light. The heads require no tools to adjust and aim are of durable polycarbonate and use 6 V, 9 W lamps or as otherwise specified. Pre-assembled for ease of installation Easy access to wiring entry Exit sign with long life, AllnGaP LED light source NEXUS compatible 30 min battery runtime