No level adjustment necessary - it adjusts itself to varying terrain as you drive. Works proportionally in reverse. Digital display depicts voltage delivery to trailer during braking. Continual diagnostics check for proper connection and shorted magnet. "Boost" feature gives the ability to apply more initial trailer braking power. Unique pocket mount. Reverse battery protection for both vehicle and breakaway systems. Designed to work with electric over hydraulic trailer brakes. Produces stops that are in proportion to vehicle's deceleration rate. Fits: 2003-2010 Toyota 4Runner 2003-2010 Toyota Sequoia 2003-2010 Toyota Tundra 2004-2010 Lexus GX470 2007-2010 Toyota Tacoma