Fit flight is different from other types of flight where it adopts push-in method that makes easy attachment possible. Angle of flight wings remains always 90 degrees. It enables a dart to fly straight to the target. Also a shaft ring is not necessary so it would eliminate obstruction when grouping. You can choose from 2 types of shafts either lock or spin. -Lock shaft locks a flight. -Spin shaft lets a flight spin. Spining flight reduces a risk of the second and thrid shots fail to land on the dartboard. �¦Fit Flight needs Fit Shaft in order to play. �¦Fit Flight that once attached to lock shaft cannot be used for spin shaft.Fit Flight AIR is designed to be 33% lighter than normal Fit flight. Wings are designed to be thinner.