Push-in Valve Cover Breather features an internal baffle to prevent oil splash and provide superior ventilation. Designed for Aftermarket Valve Covers with 1-1/4 inch breather holes that are rolled inwards, with a 1 inch outside diameter neck. Ideal for use in conjunction with the grommet kit part number 66-520. Manufactured using high quality materials, this oil filler breather cap’s triple chrome-plated steel construction ensuring it performs as well as it looks.