Its function is to detect the discharge of the fire-extinguishing agent in the immediate moment in which this one takes place. When it takes place this situation issues an electrical sign that can be used in order that the head office of fires interprets that the system has disburdened.
It has two contacts, one NC (normally closed, it opens with pressure) and another NO (normally opened, it closes with pressure) that change condition when the switch is activated and both can be used indifferently according to requirements of the installation. Also, it incorporates an interlock mechanism that it must be rearmed after every discharge in order that the device returns to work. Once activated, the rearmament must be done manually, pulling the ball towards out.