Heng's (90043-CR Vortex Fan Replacement Kit Don't just move air; 7 inch height x 17 inch Width x 17 inch length Create a Vortex Update your old; Single Speed with 9 Inch blade Inefficient powered vent easily without replacing the entire vent or compromising the rooftop seal Just replace your existing screen with the Vortex upgrade kit Make your outdated vent more powerful without buying a whole new and expensive vent