Description: Brand new and high quality Can alert the vehicles behind you to stop Can prevent rear-end collision Suitable for all 12-16V voltage input. Maximum Current Input: 2A. Specification: Compatible with all types of brake lights including LED clusters Relay dimension: 5*2.8*1.5CM Black wire -- Negative Pole; Red wire -- Positive Pole. Output wattage: 20W. Package Includes: 1 x Strobe Controller for Car brake light Note: Must first connect the power supply, and then connect the USB interface, otherwise no flash or no response