The present invention relates to a seat for a chair-lift installation composed of a seating part and a back and further including a support arch intended to be connected to a carrier cable, a safety bar mounted to tilt with respect to the seat between a lowered position and a raised position and provided with a horizontal bar. Embodiments according to the present invention can provide disk drives with optimal positioning of a fixing part of an objective lens driving unit incorporated therein. The interference pattern can create sufficient visual static to effectively obscure circuit lines in the electronic circuit when subjected to radiographic inspection techniques. An entity represents an object which exists in the physical world. The comparator is configured to output a refresh signal in response to a difference between voltages present at the first and second inputs thereof.