Yeeco AC 80-300V 45-65.0Hz Dual LCD Digital Display Voltage Meter Frequency Meter Tester Voltmeter Testing Guage Volt Monitor Panel Meter AC 80-300V LCD dual display of AC voltage and frequency in the same time With black digits and blue background, clear and easy for monitoring Voltage panel meter with international standard size,easily installed easily tested Do not need power supply, two wires just connect with AC 80-300V directly,then you can finish testing Meter only fits with pure AC 45-65HZ power supply, not be used for square wave, inverter output