The invention includes a control register for providing instructions as to basic operations such as writing, erasing, reading, etc. The tank includes at least a passage hole for supplying, discharging, or emptying the liquid metal arranged in one of its walls and extended by a mobile nozzle integral with the tank. A cover screen is arranged parallel to the directed main beam after the optical system. The unexposed outer area of The Interchangeable Headband Cover has two insertion points with overlapping flaps positioned laterally of a fused center. Then, an electrode or wiring is formed on the adhesion layer.