The 5μH Line Impedance Stabilization Network (LISN) type TBOH01 is needed to measure line noise from DC powered devices. The device has been designed for EMC precompliance tests according to CISPR 25 in the frequency range 150 kHz to 110 MHz developed according to CISPR 25, ISO 7637-2, ISO11452-2 / 4/5 and with restrictions DO-160 / ED-14G. The LISN is looped into the supply line of the DUT (Device-Under-Test). Conducted disturbances that can be found on the supply of the DUT, can be measured via the BNC connector in conjunction with a spectrum analyzer or test receiver. The TBOH01 can also be used to inject interference signals into the supply line of the DUT. Input (connection SOURCE) and output (DUT connection) of the LISN are decoupled via a 5 μH air coil.
You will find the specifications of the TBOH01 LISN here.