The MT550 is a 1000V Digital Insulation Tester easy-to-use handheld meter and has three test voltage ranges 250V, 500V and 1000V together with two continuity ranges. Whilst doing the insulation test, the large LCD will indicate the insulation resistance together with the actual output voltage. Once the test is complete the circuit under test will be automatically discharged. The MT550 features an AC and DC voltage ranges, battery voltage indication, resistance and a continuity buzzer. If AC voltage is detected, the LCD will display the actual voltage to the user except in the off position.