Trailer Brake Control Tekonsha 90185. * Prodigy: Electric trailer brake control for 1-4 axles.* Digital display depicts voltage delivery to trailer during braking.* "Boost" feature gives users the ability to apply more initial trailer braking power when towing heavier trailers.* No level adjustment necessary--It adjusts itself to varying terrain as you drive.* Works proportionately in reverse--great for backing into tough spots.* Rotary manual brake adjustment level.* Power--saving mode reduces drain on battery when vehicle is not in use.* Meets N.H.T.S.A regulations regarding tow vehicle/trailer light activation.* Limited life time warranty (some conditions apply).* This control is not designed for use with electric-hydraulic trailer brake systems.