The stock heater tube has nipples that run coolant into and out of the throttle body. This causes the throttle body temperature to be increased due to the ~200 degree fluid running through it. This modified heater tube eliminates this coolant bypass through the throttle body. The stock section of pipe right there is also very restrictive, so this modified tube will have better flow through the heater core. The tube is ground smooth and powdercoated black for a flawless factory appearance.