Fully recirculating valve. A quiet alternative to the atmospheric BOV, the Plumb Back systems vents all excess pressure back into the intake system. Ideal for cars with sensitive Air-Flow systems and off-road applications as the fully-sealed design of the Plumb Back prevents any foreign matter entering the system. Supplied with quick-release V-Band clamp, weld-on adapter. Available in blue or black, wither either 32mm or 38mm ports (please specify when ordering).