InvisiBrakeTMA revolutionary innovation in supplemental braking. NOTHING. Zip. Zero. Zilch. Nada. Nil. That"s what you have to do to connect and disconnect InvisiBrake. There"s nothing to take in and out of your towed vehicle and there"s nothing to push, pull, set, adjust, activate or deactivate. What could be easier than nothing at all?What is InvisiBrake? InvisiBrake is a fully-automatic, progressive supplemental braking system that uses the electrical connections already in place on your towed vehicle (the towed vehicle"s electrical harness) to brake when you brake the motorhome - the same electrical signal that activates the towed vehicle"s brake lights also activates InvisiBrake.Features• Completely out of sight - InvisiBrake is so small, it can usually be mounted under the driver"s seat, under the rear seat, behind interior panels or in the trunk, without sacrificing any of the vehicle"s usable space.• Progressive braking - When you apply continuous braking force, so does InvisiBrake - the longer you apply the brakes in the motorhome, the harder your towed vehicle will brake (InvisiBrake will not skid your tires).• Bypasses the 12-volt outlet and charges your battery - InvisiBrake connects directly to the towed vehicle"s battery and constantly charges the battery during towing (InvisiBrake will never drain the battery). • Two-stage motorhome monitor - InvisiBrake includes an LED monitor for a visual reference of braking activity; an audible alert at the motorhome will warn you if the brakes have been on for too long. • Activates only when the motorhome"s brake lights illuminate - no false braking! • Works in virtually any towed vehicle - including those with "active" (or "continuous power assist") braking systems. • Includes an emergency break away system• Meets U.S. and Canadian braking requirements SpecificationsController Size - 8¾" x 8¾" x 2¾"