Dirty Air Manifold - 4-ValveNew DIRTY AIR compact 4 valve manifold. Normally used to control the lift and dump functions for front and rear air suspension systems. 1 8"NPT ports, overall dimensions 2. 50" length x 2. 19" width x 2. 07" height. Each output has 2 ports for mounting plumbing flexibility, plugs are included for unused ports. Each output has its own exhaust (OUT) port, so with the addition of a flow control valve, you can slow down the front and rear exhaust