The Safety Line is a 5th line connected to the centre of the leading edge on LEI kites. For the safety system to work correctly, the bar must slide along the 5th line for a distance equal to 1 kite line.
It facilitates the relaunch of C kites, but some brands use it for structural stability of the kite, however, the depowering is less than the front re-ride system and the risk is that the 5th line may wrap around the kite as it is attached to the kite tow point (where the pump leash connects)....