DRAW TITE 5535 Trailer Brake Control (I-Command Electronic - Proportional) Requires no leveling with "up-front" buttons for easy access to Output and Boost, easily controls trailers with up to 4 axles Proportional brake control means sure, even stopping power Boost feature gives the ability to apply more initial trailer braking when road conditions warrant Diagnostic features incorporated in LED display for easy review; reverse battery protection; automatically achieves proper level and compensates for uphill/downhill travel Plug and play feature allows for quick and easy connection; bracket, mounting hardware, and comprehensive instructions included