The Prodigy P2 electric brake controller supplies power to your tow vehicle's brakes proportionally. This means that your trailer brakes at the same time and with the same strength as your vehicle - even in reverse gear. If you have to slam on your truck's brakes, the trailer's brakes respond instantly, too - there's no delay. Therefore your vehicle's brakes aren't overworked from trying to stop the entire load, and they suffer less wear and tear extending the longevity of your brakes compared to time based controls. The P2 also cuts power to the trailer's brakes when your vehicle is stopped - extending the life of the magnets and brake shoes in the trailer's brake assemblies. Aside from smoother, more efficient braking that results from proportional application of stopping power, the Prodigy P2 also has a boost feature that gives you more initial braking power for those times when you're towing heavier loads. That's when more braking power is needed to stop the trailer at the same time as the tow vehicle. The boost setting sends 13 or 25 percent more power (depending on which setting you choose) back to the trailer brakes, thus compensating for heavier loads. You can boost the power manually at the push of a button as well. The boost feature gets more power to the trailer brakes exactly when you need it most, and your fully loaded rig brakes smoothly and comfortably. This brake controller levels automatically as you drive, so there's no problem using it on steep hills or when towing through the mountains. The self-leveling feature also makes the Prodigy easy to install: Simply mount it in your cab at any vertical angle (it has 360-degree rotation). It's easy to see the display and to access the pivoting manual override lever on the bottom of the unit. The P2's continuous diagnostic check monitors your connection and magnet condition, so you can fix any problems before they land you on the side of the road. This newest version of Tekonsha's popular Prodigy brake controller has reverse battery protection to preserve the unit and accessory systems. And the power-save mode reduces battery drain when the controller isn't in use. The included mounting pocket makes your brake controller portable. Your unit slides out of the pocket mount for easy transfer of the brake controller to another vehicle. After selecting the proper optional (sold separately) harness for your vehicle, one end of the pigtail harness plugs directly into your vehicle, while the other plugs into your P2. Just unplug the unit to move it to another car, truck or SUV use or simple storage - no hard-wiring required. An instructional DVD that is included with the brake controller's written instructions allows you to take full advantage of all the features.