Signal Dynamics The Original Backoff Brake Light Module 01001 Compact solid state module converts your ordinary brake light into an attention getting visual alerting device, more visibility and conspicuity when you are stopped or stopping With BackOFF installed, when you apply your brakes, it causes your brake light to automatically emit a visual alerting signal of 3 short light flashes, followed by 1 steady on light condition of 3.5 seconds Signal automatically repeats itself as long as the brakes are applied Compact size. - 2-1/4in. L x 1-5/8in. W x 5/8in. H