All vehicles built after mid 1997 do not have heater control valves. There is no way of manually controlling coolant flow through your heat exchanger, unless you have an ITAP. This lever valve tap allows you to vary coolant flow and resultant output shower temperature. A must for vehicles which run too hot even at idle.Please note that the only time the ITAP valve is to be varied is when showering, the rest of the time it is to remain wide open. Comes with 5/8" barbs and TRIDON radiator clamps, ready to install. It must be installed in the coolant feed line ie BEFORE the coolant reaches the heat exchanger.