Fitted in place of the original demister unit, this system works in the same way as the original heater unit but replaces the original heater element with a uprated heater element combined with a high efficiency evaporator core, drawing air from the bonnet duct before venting into the car through the original plenum chamber. The system is full fresh air and the improvements in air flow and cooling are impressive. A bonus is extremely effective heating/demisting which also dehumidifies, ridding the car of the inevitable condensation when it rains. Additional driver/passenger facing vents are advised to maximise performance.