Today, we'll be reviewing Part Number HA81792BB. This is the Hayes G2 Brake Boss Trailer Brake Controller with Mounting Sleeve for 1 to 4 Axles. This brake controller is going to activate your trailer brakes in proportion to your vehicle's braking action. That automatically adjusts the trailer's brakes based on deceleration of the tow vehicle, and it activates immediately, so there's no pausing… see more >