M89B Voltage Frequency Meter Panel Digital Voltmeter AC Meter AC50-500V 10.0-99.9HZ Built-in Household InstallationOOTDTYComs: AC Voltage Frequency Meter 50-500V LED Display of AC Voltage and Frequency at the same time. Frequency range: AC 10.0-99.9HZ, auxiliary power: 2 wires AC50-500V. The data is more intuitive, dual-color LED display, red+green, clear and easy to monitor at a glance. This voltage frequency meter is easy to install, built-in installation, more stable. The meter only fits for pure AC power supply 50-60HZ, can not be used for square wave, inverter output. Specification: Material: Plastic Size: 70x40x2 5mm/2.7x1.6x1.0in Measuring Range: AC 50-500V, AC 10.0-99.9HZouction: 2 Wires AC50-500V Package Includes: 1X Voltage Frequency MeterNote: Please allow 1-3cm error due to manual measurement. Pls make sure you don't mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item.