Abstract: An apparatus for the transmission of the pressure in the sterile area of a medical appliance to a non-sterile pressure gauge has two housing halves and a sterility filter positioned between the two housing halves. The filter is supported by a backing. The housing half on the sterile side is made of polycarbonate. The non-sterile half of the housing is made of a polymer, preferably a polyester/polyether copolymer, which provides an easily disconnectable and leak-proof connection with the pressure gauge. The two halves are ultrasonically welded together.