Since it is sometimes necessary to monitor pressures in areas exposed to explosion hazards, the type 901 pressure switches by Beck and the type 930.8x differential pressure switches where subjected to a design type test. As a result of this successful test, the pressure switches of the 901 series are now labelled II 1/2G Ex ia IIB T4 and are suitable for use in zones 0, 1 and 2 or are labelled II 2G Ex ia IIC T4 and suitable for use in zones 1 and 2. The differential pressure switches of the series 930.8x can also be used in gaseous atmospheres and have been awarded the Atex labelling II 2G Ex ia IIB T4. All devices have the ignition protection type intrinsic safety and were graded as temperature class T4 and explosion group IIB and IIC. The devices are available with pressure connections in a wide variety of materials, shapes and sizes. The membranes are also available in many different materials. Setpoints can be set individually from a few Pa up to 12 bar.