Fitment Information  Honda Civic Si 1.5L (2016, 2017, 2018, 2019)  Honda Civic Sport 1.5L (2017, 2018, 2019)  Emissions Compliance This item has not been CARB certified so it does not ship to California Specs & Features Direct Bolt On 44 Piston w/ Viton O-Rings Fast Response Allows you to run high boost pressure This is a direct bolt-on replacement for the factory bypass valve and was designed to the be THE BEST blow off valve on the market. Using a large 44mm piston and Viton O-rings to withstand the high air charge pressures and outlet temperatures from your turbocharger.  Made in the USA, every detail on this valve screams quality and precision, right down to the position of the Hybrid Slot and shape of the Vent to Atmosphere Port making that perfect “Psssh” between shifts. Anatomy of the Best Valve Ever: The Design is a exercise of Function Aesthetic. The crown of the cap is notched perfectly for placement of fingers making it easy to tighten, loosen or remove.  The custom machined 304 Stainless Steel banjo fitting with low profile 10mm banjo bolt is pure automotive jewelry. The Hybrid Inlet Slot is aligned perfectly to the OEM Outlet slot for smooth airflow.  The center Recirculating Outlet allows some of the air to flow back to the turbocharger inlet keeping the ECU happy and your car Check Engine Light free.   The Vent to Atmosphere Ports are positioned around all three sides of the valve to give you and everyone around you that perfect “Psssh!” between shifts. The ports themselves feature a megaphone-style design for maximum sound levels. Each 6061 aluminum valve is anodized for beauty and durability in your choice of Red, Blue, Gray or Black.