The Elring Trans Oil Cooler Line O-Ring - 519330 is a small, circular rubber seal designed to fit onto the oil cooler line of a vehicle's transmission. It helps to create a tight seal between the line and the transmission, preventing any leaks or loss of fluid. This O-ring is made by Elring, a reputable manufacturer of automotive parts, and is specifically designed for use in transmission systems. It is durable and reliable, ensuring a long-lasting seal for your transmission.