The F-33-4 is for use with the CIPPR 22 testing. The F-33-4 has a nominal transfer impedance of 1W (±2dB) from 400 kHz to 100 MHz and exhibits less than .3 dB variation across this band width. It has an insertion impedance of <.5 dB 1 kHz - 30 MHz and adds <2 pf of capacitance to the line under test.