High-brightness LED display: One LED displays real-time voltage, It is clear and convenient to read. Wide measuring range: AC 60~500V, 50/60HZ, with high accuracy of 1%±2 digits. 2 Wires to connect: For the user, operation is incredibly simple: just connect the two plug-in terminal wires to an external power source. Ultra small size: 2.68×1.65×1.5inch / 68x42x38mm. No extra individual power supply, this volt meter can be installed on anywhere flexibly. More information: Operating temperature: 14°F~149°F/-10 ~ 65. Note: The AC 110V/220V voltage meter only suits for pure AC 50-60HZ power supply and can NOT be used for square wave, inverter output and sine wave circuit measurement of modified sine wave, otherwise the meter will be damaged.