The Genuine Porsche Engine Oil Dipstick O-Ring - 99970740240 is a small rubber ring designed to fit onto the engine oil dipstick of a Porsche vehicle. It is used to create a tight seal between the dipstick and the engine, preventing oil from leaking out. This O-ring is an authentic Porsche product and is made with high-quality materials to ensure durability and proper function. It is an essential component for maintaining the proper oil level in a Porsche engine and should be replaced if it becomes worn or damaged.