This Screwdriver Small 1/8' Magnetic Tip Perfect for Bobbin Case Tension is the perfect tool for adjusting tension on your bobbin case. It features a new 1/8' magnetic tip that is perfect for adjusting bobbin case tension. The small size makes it easy to store and transport, and the magnetic tip ensures that screws stay in place while you work. The total length of screwdriver is 3 7/8 inches.