A split pin drive shaft nut is a fastening device specifically designed for the Citroën 11CV and 15CV models. It is essential for securing the drive shaft to the vehicle, ensuring a safe and effective transfer of engine power to the wheels. The nut features a split pin, acting as a locking mechanism to prevent the nut from loosening during operation. It combines durability with simplicity in installation, which is crucial for maintaining the reliability and performance of these classic cars. This component is integral to the maintenance and restoration of these iconic vehicles.