Abstract: A combination includes a feedthrough element for an electric high-frequency signal in a TDR level metering device, and a probe for guiding the high-frequency signal from the feedthrough element to the filling product surface of a filling product to be measured and back. The feedthrough element includes at least one guiding element (6), into which the electric high-frequency signal is to be fed at an inlet point (10), and which transmits at an outlet point (17) the electric high-frequency signal to a probe (7) adapted to guide the high-frequency signal, a one-part or multipart mechanical carrier element (1), and a one-part or multipart insulation (11, 12) present between the carrier element (1) and the guiding element (6). In the combination the impedance of the feedthrough element and the impedance of the probe (7) following the outlet point (17) are substantially matched to each other at the outlet point (17).