When measuring pressure or underpressure, the filter type FT-S protects the unused connection of our devices against dust an dirt. The use in outdoor areas is not permitted. The sinter filter absorbs humidity and can therefore falsify the measuring result. The filter is screwed with the internal thread (G1/8I for 64 or 64POM, M12x1 for 86 or 86POM) directly onto the thread of the screw connection on the device.