Signal Dynamics BackOFF XP Brake Light Modulator Help those zoned-out drivers see you better! This compact solid-state electronic device converts an ordinary brake light into a high attention-grabbing alert signal when you are stopped or are stopping. When you apply your brakes, BackOFF will automatically flash your brake light three times, then hold it steady for 3-1/2 seconds. This pattern is not random, it was selected for its ability to keep the attention of the drivers behind you. Features: Signal LED pattern is repeated as long as the brakes are applied Installs in minutes with two connections Works with LED and standard bulbs Sold each