Vance & Hines Naked VO2 Skullcap Air Cleaner Insert (CHROME) Add a touch of class to your VO2 Naked Air Intake with a Vance & Hines VO2 Skullcap. Styled with subtle creasing reminiscent of an old school mag wheel, the VO2 Skullcap consists of a single steel stamping that bolts directly over the air filter element.Available in either chrome or black ceramic.Note: VO2 Skullcap will also fit Screamin'