The cylinder head nut, also known as a cap nut, for the Citroen 11CV Perfo and 15CV is an essential fastening component specifically designed for these classic vehicles. Made of high-quality steel, it provides a secure and reliable connection between the cylinder head and the engine. This cap nut helps prevent leaks and ensures the engine operates efficiently. Regular maintenance and replacement of these nuts are crucial for maintaining the vehicle's performance and longevity. They offer not only functionality but also contribute to the historical authenticity of your classic Citroen.