This insulation tester features excellent test voltage regulation, direct measurement readout, and an external guard terminal for eliminating surface leak current from the measurement. Ideal for general purpose testing, this tester is portable and self-contained and designed to give rapid and accurate measurements. The analog display has four selectable test voltages of 100, 250, 500, and 1,000 VDC for measuring insulation resistance up to 2,000 MΩ and has as ohm range to 5,000Ω. This insulation tester (EDMO# 212159) features a hand-cranked power generator as its power source that is easy to turn even under full load situations. The accuracy remains unaffected by variations in generator cranking speed and test voltage is maintained at its rated value.