Prepare your semi to be Ready for the Road Ahead , with the OTR 12/24V 112 dB Heavy Duty Back-Up Alarm that offers proper alarms to notify spectators of a reversing vehicle. Due to its direct connection with the reverse mechanism, this replacement component is able to create an audible sound any time a vehicle is in reverse. Constructed with a weather-resistant design to operate in all types of environments. FleetPride is your First Click in Heavy Duty .