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 the 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 power-save mode reduces battery drain when the controller isn't in use.