The “F5” series pressure switches activate a microswitch once a preset pressure value is reached. The preset pressure is set by rotating the internal screw located at the centre of the instrument, clockwise to increase the value and vice-versa to decrease it. The internal screw is accessible by removing the protection plug. Mechanical stops protect both the spring and microswitch from overpressure. Of compact and economical construction, it is suitable for system not requiring a constant modification of the intervention point; conversely, the possibility to block the protection plug can avoid unwanted or unintentional changes of the value.