Spectre's Oil Filler Breather Cap Twist-In features an internal baffle to prevent oil splash and provides a secure tight seal with superior ventilation. This cap can be used with all twist-lock type filler holes, including with oil filler extensions. Manufactured using high quality materials, the oil filler breather cap is triple chrome plated steel ensuring it performs as good as it looks. Note: Legal in California only for racing vehicles which may never be used, registered, or licensed for use upon a highway. See spectreperformance.com for CARB status on each part for a specific vehicle.