Spectre's Valve Cover Breather Push-in features an internal baffle to prevent oil splash and provide superior ventilation. This valve cover was designed for 1-1/4 inch breather holes, with a 1 inch outside diameter neck. Ideal for use in conjunction with the grommet kit part number 5339, this breather includes a replaceable internal foam insert. Manufactured using high quality polished aluminum, this oil filler breather cap features a smooth design to ensure it looks as well as it performs. 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. Spectre s Valve Cover Breather Push-in features an internal baffle to prevent oil splash and provide superior ventilation. This valve cover was designed for 1-1/4 inch breather holes; with a 1 inch outside diameter neck.