Feature:1. Fitment: Boost pressure control valve is replacement for Vauxhall Astra G Models 19982004 With Z20LET Engines, replacement for Vauxhall Astra H Models 20042009 With Z20LEL, Z20LER, Z20LEH Engines.2. Part Number:The reference number of the valve are 55557806, 55352099, 5850129. Please check the part numbers whether it suits your vehicle before purchasing.3. Basic Principles: Compressing air to increase the air intake, using the inertial impulse of the exhaust gas from the engine to push the turbine, increasing the output of the engine.4. Durable Construction: The boost pressure control valve is made of ABS, which is hardness, rust proof, not easy to deform, sturdy and durable.5. Simple Installation: The installation is simple, direct replacement for the old or broken one, no modification is required, convenient for using.Specification:Item Type: Boost Pressure Control ValveMaterial: ABSReference Part Number: 55557806, 55352099, 5850129Application:Replacement for Vauxhall Astra G Models 19982004 With Z20LET EnginesReplacement for Vauxhall Astra H Models 20042009 With Z20LEL, Z20LER, Z20LEH EnginesReplacement for Vauxhall VX220 Models 2001-2004 With Z20LET EnginesReplacement for Vauxhall Zafira B Models 2005-2012 With Z20LER, Z20LEH Engines.Package List:1 xBoost Pressure Control ValveNote:1.Please double check the part number of your item, matching information is for reference only.2.If you are unsure of the item, please contact us before buying to avoid unnecessary return, thanks!