Tomei Adjustable Cam Gear Exhaust Left Single AVCS Motors 2006-2014 WRX / 2004-2007 STI / 2005-2009 Legacy GT

Adjustable Cam Gears allow fine tuning of the camshaft timing to maximize engine performance and tailor power characteristics for various driving conditions. Whether you have OEM or aftermarket Camshafts, adjustments can be made to tune an engine's power band to the optimum RPM range for a particular application. 

This is for single AVCS cars and for the left hand side only. You will also need to purchase the right hand side to complete the installation.