The Sound Off Signal Flashback rear flasher system flashes your lower brake lights against backup lights at 2.4 flashes per second to provide an additional warning signal to the rear. Must be wired to an isolated on/off switch. Installs in most vehicles with a 12VDC negative ground system. Please contact us if you are not sure if this unit is compatible with your vehicle. Specifications: 12 Volt DC Current: 9.5 Amps per output Measures 4.7"L x 2"W 5 YEAR WARRANTY