Unfortunately, the test probes are too thick for a Swiss type J socket (e.g. T13). Although the probes fit into the plug contacts, they can neither be sunk deep enough nor angled in the direction of the contacts, which means that no contact can be made with the plug contacts. This limits the application in the area of the Swiss NIN to (the rather rarer) measurements of luminaire terminals or similar. Types E and F (French system or German/Austrian Schuko), on the other hand, can be measured without any problems, as the plug contacts here are designed with a larger internal diameter as standard. Interestingly, an Internet search for the type designation of the device reveals the operating instructions of a German manufacturer, which advertises the use in a German Schuko (type F socket). Unfortunately, it seems that this is probably an imported device that has not been sufficiently adapted to local conditions.