GGB PicoProbe the high-frequency product series are as follows: Model 50 (33 - 50 GHz / WR-22 waveguide input) Model 75 (50 to 75 GHz / WR-15 waveguide input) Model 90 (60 to 90 GHz / WR-12 waveguide input) Model 120 (75 to 110 GHz / WR-10 waveguide input) Model 140(90 to 140 GHz / WR-8 waveguide input) Model 170 (110 to 170 GHz / WR-6 waveguide input) Model 220 (140 to 220 GHz / WR-5 waveguide input) Calibration Substrates (for probe tip calibration - available in 9 standard models) Differential Calibration Substrates (for two, three or four port probe tip calibrations )