Grand General's Fleet LED (light emitting diodes) lights offer an inexpensive way to upgrade your vehicle lighting. LEDs are brighter and have lower ampere draw making it possible to add more lighting without upgrading your charging system. 4 inch round lights are a commonly used size in heavy and medium duty trucks. This red 4 inch round Fleet LED is used for stop/turn/tail functions and uses a 3-pin round pigtail. The Fleet series is DOT (Department of Transportation) compliant for street legal lighting and is an excellent value choice.