An ACDelco Professional, premium aftermarket Engine Oil Filler Cap is a threaded or quarter-turn cap that seals the oil filler opening on your vehicle's engine, and is a high quality replacement for many vehicles on the road today. It has a rubber sealing ring that keeps the engine oil and crankcase vapors in, while keeping water and dirt out. This premium aftermarket replacement engine oil filler cap is manufactured to meet your expectations for fit, form, and function.