The R&S®ENV4200 from Rohde & Schwarz is a Line Impedance Stabilization Network with AC Voltage 0 to 690 V, Frequency 150 kHz to 30 MHz, Inductance 50 uH, Isolation 40 dB, Maximum Continuous Current 200 to 250 A. More details for R&S®ENV4200 can be seen below.