... knob can quickly adjust the voltage and frequency. 2.High precision, screen digital display: frequency, voltage, current, power, power factor. 3.Quick ... % load/ unload in 2ms. 4.Output frequency: 50Hz, 60Hz, 47 ~ 63Hz (can be a special custom-made to the 35-400Hz) 100Hz ... (optional), 200Hz (optional), 400Hz, load frequency stability of ± 0.1 ...