Replaces stock fan clutch when maximum air flow is necessary for additional cooling on vehicles driven at engine speeds under 4200 RPM. Works with stock fan blades. Mounting hardware and step-by-step instructions included. Fits bolt hole diameters 2-3/8'' to 2-5/8''.

Note: Fuel economy will drop because fan blades spin constantly for full time cooling. Not for use on high performance engines.