Dual outlet-type BOV. Dual Port vents both to the atmosphere and back into the air intake. Ports with sequential timing allow quieter operation during everyday driving, while getting all the benefits of a vent-to-atmosphere BOV under race conditions. They are easily converted to a complete atmospheric or whole bypass unit by using supplied port blanking plug.
Please note; that for twin-turbo applications, such as the Audi S4 2.7L (B5) 97-01, this will require two valves.