The Model BA-1697WN back-up alarm is designed to provide aWHITE NOISE "PSSS-PSSS"warning sound along with a bright flashing light to alert people of the hazardous condition of a vehicle being operated in reverse. The loud 97 decibel alerting sound and 3-watt LED flashing light will automatically turn on when the vehicle is in reverse. Built with advance electronics that allows the driver to turn off the audible beeping sound or the visual flashing LED, on demand. (does require installation of a toggle switch in the driver compartment, switch not included.) State-of-the-art electronics are sealed in rock hard epoxy to protect for all weather usage. Automatically adjusts to a voltage range of 10-80 volts DC. The case is made of ABS plastic and has strong mounting brackets, that can withstand vibration. There are no bulbs to burn out and the PRO-TEC PLUS is totally maintenance free.