Toolcraft expansion pins made of spring steel according to DIN 7346 standard, designed for secure fastening applications in bicycle headsets. These expansion pins have a diameter of 21 mm and a length of 40 mm in a lightweight design, providing reliable mechanical connections in bicycle components. Made from high-quality spring steel, these pins offer excellent durability and consistent performance under bicycle operating conditions. The DIN 7346 certification ensures standardized dimensions and quality compliance for bicycle headset bearing installations. Each pack contains 25 expansion pins, sufficient for multiple bicycle assembly or repair projects. These components are designed for precise fitting in bicycle headset systems, ensuring correct alignment and secure attachment of headset bearings. The spring steel construction provides resilient holding power while allowing controlled expansion during installation. Suitable for professional bicycle mechanics and cycling enthusiasts who need reliable fastening solutions for headset maintenance and assembly. The standardized dimensions ensure compatibility with bicycle frames and components designed for 21 mm expansion pin applications. These expansion pins support proper headset function by maintaining bearing alignment and preventing component movement during bicycle operation. The lightweight design balances strength with weight considerations for bicycle applications where component weight is relevant. These pins are engineered to withstand vibrations and stresses in bicycle use while maintaining secure fastening integrity over extended periods.