Product Details: Prepare your semi to be Ready for the Road Ahead™, with the Wabco Trailer ABS 4S / 2M Electronic Control Unit Kit that provides enhanced brake control in demanding or slick operating conditions. Due to its direct connection with the wheels, this control unit is able to determine when to release brake pressure to prevent lockup or sliding. Constructed with an advanced microprocessor to identify optimal brake release times and repair needs. FleetPride is your First Click in Heavy Duty®.