This True Megohmmeterhas test voltage combinations of 500V, 1000V, 2500V and 5000Vand insulation measurements from 30KO to 10,000GO (10TO). It also has selectable and programmable test voltage (40 to 5100V); automatic calculation of DAR, PI and DD ratios; direct measurement and display of capacitance and leakage current, and display resistance, test voltage and run time. In addition, it has programmable test run times and PI ratio times; smooth and alarm functions;automatic test inhibition if live sample (>25V); automatic discharge and display of discharge voltage;large dual display with time, voltage and measurements shown (Models AE213020 and AE213021); graphic and digital display of test voltage, resistance and more (Model AE213030);bright blue electroluminescent backlight; programmable test voltage lock-out; programmable alarm setting, and auto power-down when not in use. The Megohmmeter is AC or DC powered with rechargeable NiMH batteries