Edwards Signaling 1900MS12-24 is an accurate long-life LED time display piece that can be operated in a synchronized clock system. It reports time in 12 hour or 24 hour formats with hour and minute that may be dimmed at the flick of a switch. An 18 foot cord is connected to a Class 2 transformer which plugs into a standard wall outlet. For indoor operation only. The units may be wall mounted indoors in temperatures of 32° - 120°F (0° - 49°C). Designed for indoor display of time by hour and minute in 12 hour or 24 hour format.