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.