An LED (light emitting diode) is an efficient, effective and ultra bright alternative to incandescent light bulbs. Unlike traditional light bulbs, LEDs do not burn out; they just slowly dim over a long period of time (about 100,000 hours or 11+ years). An LED sign is made up of individual modules of about 12 inches square each with LEDs mounted on them. The modular design allows the signs to be configured to almost any size. LED signs are typically double-sided and are available as monochrome or full color. A common size for commercial LEDs is 37" high x 8' wide. Messages are programmed and scheduled on the signs using software installed on the computer that controls the sign.