The Kayser 3.023.348 Diverter Valve is the upgraded factory valve from the 225hp Audi TT (Audi part #06A 145 710N). Kayser has replaced Bosch as the OEM manufacturer. The latest 710N valve, as it is commonly known, helps reduce surging that may occur when modifying your 1.8T's engine. The 710N valve has a 14.4 lb. spring internally rather than an 8.8 lb. spring.