Mr. Gasket 2054BP Flat Black Push-On Breather Cap with PCV Tube A fast easy way to help customize your engine compartment with that stealth look Engineered for high performance street vehicles with positive crankcase ventilation and race cars with vacuum balance systems 1 inch outside diameter necks and .625 inch breather tubes with an integral metal baffle and foam element Designed specifically for small block Chevys Fully compatible with all factory and aftermarket valve covers with a 1.250 inch hole Top Material/Finish: Chrome