This, 3-7/8″ Back up Alarm, Velvac, 697107, back up alarm from Velvac is just what you need to safely reverse your vehicle. This high-quality back up alarm is available in a classic black. A center mounting ensures simple application. It has a voltage of 12 to 24VDC. It is 3-7/8″ long. Back up alarm, 97 decibels 100-200 amps 3.25 mounting hole centers 12V wiring instructions included easy installation.