RCM Gobstopper Arrow 75mm Billet Crankshaft Filters Their prime purpose is to

Their prime purpose is to reduce emissions from cold idle to meet standards governed by the EU emissions regulations (similar regulations also exist for both the US and Japan)

Direct Fit for Subaru Impreza GDA/GDB (2001–2007)

ACL's reputation speaks for itself

On the end of the cap is the STI logo to compliment your Subaru

but also includes a power booster which increases the energy in the fuel

RCM Gobstopper Arrow 75mm Billet Crankshaft Filters Their prime purpose is toQuality. Innovation. Performance. The hallmarks of Arrow Precision. Only the highest quality raw materials, the latest methods and the knowledge of superbly skilled designers and engineers goes into the making of every Arrow Precision part. At the heart of every Gobstopper engine you'll find the Arrow crankshaft, the ultimate piece of British Engineering designed to withstand the most extreme engine loads. Engineering precision detailed cranks begins