These nylon spring shafts have a 2BA thread and are more durable and more flexible than our standard nylon dart shafts. The nylon spring shafts feature a spring ring clamping system to help hold the dart flight firmly in place and to help eliminate flight throw out caused by vibrations sent down the dart when the dart hits the dartboard.To correctly measure a dart shaft length measure the length of the actual dart shaft itself, the threaded section is not included in the measurement.Dart shaft lengths: Extra Short (28mm), Short (37mm), Standard (50mm).Each pack contains 3 x 2BA nylon shafts with clamping springs.