This is a reverse pattern Pro Tree style transbrake valve body for the 1970up C4. Low/reverse band is applied in 1st gear for engine braking and for sprag protection. A must for high horsepower in heavy vehicles. Solenoid activation is not required for reverse gear which allows for more convenient street use. Uses external type solenoid which provides a faster release compared with internal type solenoid set ups as well as easier service. Valve body will fully function as a reverse pattern full manual valve body even if power to solenoid is lost or solenoid is not hooked up. For use with push in style modulators. We also have screw in style available, please call for price.