It is equipped with an oscillating mechanism. This feature allows a movement of the mast that supports the seat and backrest assembly. It moves from the folded position next to the table; to the working position when the student takes a seat.
When the SD 777 is folded, it allows wide spacing between rows, since the closed envelope measures. Similarly, when the student is seated, the seat can be moved to a more forward position by tilting the body forward to increase the rear circulation area.