The AccuAir VX4 is a 4 corner manifold valve that features state-of-the-art technology rolled into one amazingly compact package! This new manifold features filtered 3/8" PTC ports with VFC (variable flow control) technology - sounds fancy, right? In short, it means that you can control the speed of airing out with a simple adjustment located on the valve block. The AccuAir VX4 is an eight solenoid manifold which is designed to control four corners. If you're looking for something to only control two corners, check out the VX2 2 corner valve manifold!