Pressure switches with bourdon tubes are pieces of equipment with safety functions as set down in the Pressure Equipment Directive (PED). They are suitable for protecting the pressure device should the pressure rise above, or drop below, the approved boundary limits. These pressure measuring devices may only be operated with the electrical evaluation units set out below, and within the area of application of this certificate and the VdTÜV component identification number. Because of its robust design, it is suitable for use in tough environments.