CVOs with Variable Valve Timing (VVT) require a special tool when you want to work inside the cam chest. S&S designed this Cam Phaser Tool that holds the cam phaser assembly in place to allow you to pull the 25400447 Spool Valve Bolt and get access to the cam plate, oil pump, and, of course, the cam. If you’re going to work inside the cam chest of these CVO VVT models, you'll want this tool.