Model 35 (dc to 26.0 GHz, 1.25 Megohm/0.05pF)
Model 7 and Model 7A(dc to 500 Mhz, 50 ohm)
Model 12C(dc to 500 Mhz, 1 Megohm/0.1pF)
Model 18C and 19C(dc to 350 Mhz, 10 femtoamps/0.02pF)
Model 18C and model 19C(dc to 350 Mhz, 10 femtoamps/0.02pF)
Model 34A (dc to 3GHz)(dc to 3.0 GHz, 10 Megohm/0.1pF)
Model 28 and 29(dc to 1 Ghz, 10 femtoamps/0.04pF)
