Toolcraft expansion pins, dimension 21 mm x 30 mm, manufactured from spring steel according to DIN 7346 standard in light execution version. These precision expansion pins provide reliable fastening solutions for mechanical assemblies and bicycle components, specifically designed for headset applications where secure mounting is essential. The spring steel construction ensures excellent durability and resistance to deformation under load, maintaining consistent clamping force over extended use. With a diameter of 21 mm and length of 30 mm, these pins offer precise fitment for standard bicycle headset systems. The light execution design provides optimal balance between strength and weight considerations. Each pin features the characteristic expansion functionality that creates firm, vibration-resistant connections in assembled components. Supplied in a practical quantity of 50 pieces, this set accommodates multiple installation requirements or serves as convenient workshop stock. The manufacturing quality ensures consistent dimensional accuracy across all pins, facilitating straightforward installation and reliable performance in cycling applications where precision alignment and secure fastening are critical for optimal bicycle handling and safety.