We recommend servicing your valve every 3 years, or 20,000 miles, whichever comes sooner This is a piston design recirculation valve that is a direct replacement for the original fitment. This valve gives greater longevity than the diaphragm valves (OEM) but also benefits from its ability to be fitted with different springs when the boost pressure has been increased or the engine has been modified. To ease installation the top or vacuum connection is angled. Please note for Porsche 997 Generation 1, x2 FMDVK04S's are required.In The Box: 1 x FMDVK04S Valve 1 x Uprated Yellow Spring 1 x Forge Sticker If you wish to tune this product to fit the needs of your engine, please see the spring tuning kit below. Please note: In certain car models the removal fo the O. E mounting bolts may be better facilitated by grinding down the short leg of the appropriate Allen key to 10mm long. This item is in the category "Vehicle Parts & Accessories\Car Tuning & Styling\Air Intake & Induction\Dump, Bypass & Blow-Off Valves". The seller is "wg_motorparts" and is located in this country: GB. This item can be shipped worldwide.