The Rein Crankcase Breather System Kit - 137972 is a comprehensive kit designed for use in cars. It includes a variety of products to help maintain the crankcase breather system in optimal condition. The kit contains a breather hose, a breather valve, a breather pipe, a breather filter, and a breather gasket. These components work together to regulate the pressure in the crankcase and prevent any excess pressure from building up. This helps to improve the overall performance of the car and reduce the risk of engine damage. The kit is suitable for use in a range of car models and is an essential component for proper engine maintenance.