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 materials, this oil filler breather cap's triple chrome-plated steel construction ensuring it performs as well as it looks. Product Features:Triple chrome-plated finishHigh quality steel construction1 inch outside diameter neckFeatures a replaceable foam insertUse with grommet kit part number 5339