The LF-K 7 is a passive near-field probe. In contrast to the LF-U 5 probe, the LF-K 7 probe does not detect field lines entering the probe head laterally.

The near-field probe detects inhomogeneous magnetic fields which enter the bottom of the probe head through one coil, curve circularly around the head and exit through the second coil. Superposed homogeneous fields are not detected by the special probe head. The near-field probe is small and handy. It has a current attenuating sheath and, therefore, is electrically shielded. It can be connected to a spectrum analyzer or an oscilloscope with a 50 Ω input. The H-field probe does not have an internal terminating resistance of 50 Ω.