Proportional Electronic Trailer Brake Controller for Virtually Trailer with 2 to 8 Braking System Replace 8508211 (Proportion) Product Description 【Intelligent braking】Proportional controllers are the safest and most responsive braking system you can install.Proportional trailer brake controllers automatically sense when your tow vehicle slows down or stops. This type of brake controller will replicate your own braking intensity for your trailer's brakes — whether you slow to a gradual stop or have to slam on your brakes. 【Easy to display】LED Digital display screens show the voltage delivery going from the brake controller to the trailer's brakes. Easy to read, easy to observe vehicle conditions in real time.In case of emergencies, make adjustments in time. 【Safer and more stable】Fits 1 to 4 axle (2 to 8 brakes) trailers to deliver a signal from your vehicle's brakes to your trailer,both quantity of braking power (result) and rate of the program (sync) can be adjusted to fit your inclination, the street conditions, and kind of trailer,increase the safety of driving.Requires no leveling. 【Quick installation and use】Wiring ports are available for vehicle-specific brake controller harnesses and provide a quick connection between the controller and the towing vehicle for quick and easy installation or removal. 【Muti-function】Brake Control for Trailer Tow,for example: RV, trailer, truck, sightseeing car. 1.Real-time monitoring, easy to observe and adjust. 2.Trailer towing is safer and more stable. 3.Fits 1 to 4 axle trailers. 4.Easy installation, plug and play. 5.Fits most vehicles.