GFB pioneered the Hybrid system back in 1998 (which has since been copied by many other manufacturers), featuring two venting outlets, one is a recirculation outlet and the other dumps to atmosphere. This system means that about 50% of the air is recirculated, resulting in an audible but slightly more subdued blow-off noise. It also means that certain Audi/VW, Nissan, Mitsubishi and other cars with sensitive airflow meters can use this valve and make a great blow-off sound without backfiring or ECU error codes. No other manufacturer can boast such success with these types of cars. The latest version of the Hybrid allows the user to vary the noise characteristics of the valve, essentially making the Hybrid three valves in one! By swapping either the trumpet or the recirc outlet for a special plug (now supplied), you can change the valve to 100% recirc (silent), 50/50 recirc/atmosphere (medium noise), or 100% atmosphere (loudest).     Colours available: red, blue, or silver.