Exhaust Rain Caps are for protection from the rain and outdoor elements on truck exhaust systems.The exhaust cap closes when the engines are stopped or idling slowly to protect the engine systems on trucks, tractors and heavy machinery.Easy to fit in sizes from 25mm to 200mm diameter. For sizes 114mm and upwards Mercury brand zinc plated caps are supplied these caps are precision balanced with nylon stops to ensure quiet operation. Mercury caps are made in U.S.A. and are used as original equipment by most heavy truck manufacturers. Chrome and stainless steel caps are available on application. Contact us for a discount code prior to placing an online order or purchase by phone or email.