Prepare your semi to be Ready for the Road Ahead , with the OTR 12/24V 97 dB Back-Up Alarm that offers proper alarms to notify spectators of a reversing vehicle. After a vehicle is shifted to reverse, this replacement component makes an audible sound to promote safety and prevent potential accidents. Built with a durable weather-resistant construction to operate in all types of environments. FleetPride is your First Click in Heavy Duty .