Clutch Kit Clutch Pro KRE22407 SL 04 The fresh air valve allows Type:ZF S5D Petrol The fresh air valve allows for incoming charged fresh air from the turbo to be diverted safely into the exhaust manifold pre turbine wheel with the throttle at low opening angles to allow for safer spooling of the turbocharger without the potentially damaging throttle based late combustion event style anti lag that can induce high engine stresses and break connecting rods Upgrading with the same base pressure as factory clutch components Clutch Pro has a reputation throughout Australia and now in Europe for supplying the highest quality original equipment type clutch kits