| | | For the seals of the cases O-rings of Silicon and NBR rubber are used. The Silicon O-rings seal the two case halves up. They are insensitive and must not be greased. O-rings made of NBR caoutchouc are used for the insulation of the operating devices, ports and plates. The strength of the O-rings are chosen in such a way that they offer the greatest possible thick area, only in this way a greatest possible safety is ensured. | | |