The HP / Keysight 35676B Transmission / Reflection Test Set operates in conjunction with the internal calibration routines in the HP 3577A and HP 3577B Network Analyzers. The HP 35676B Reflection / Transmission Test Kits contain components to assist the 3577A Network Analyzer in performing calibrated complex reflection and transmission measurements over the frequency range of 5 Hz to 200 MHz. The 35676B has a 75 Ohm test port impedance while the 35676A has a 50 Ohm test port impedance.