4. SUPER SMALL SIZE: With 68x68MM hole size. This voltage frequency meter can be installed on anywhere flexibly, compact and convenient. 3. NO EXTRA INDIVIDUAL POWER SUPPLY: Voltage frequency meter can directly connect two wires to the tested voltage to measure voltage and frequency without power supply. 2. WIDE MEASURING RANGE: Digital AC voltmeter frequency meter can measure voltage of AC 50~500V, frequency 10.0-99.9hz, accuracy is 1% ± 2 digits, with high working efficiency of 2 times/s measuring speed. 1. The LED AC voltage frequency measuring instrument is mainly used for real-time measurement of the AC voltage frequency in the electrical circuit, and uses the LED digital tube display to display in digital direct reading mode. 5. CLEAR AND INTUITIVE DISPLAY: Voltage frequency tester uses a 0.56in LED font size to display the distribution of data in a concise form, so that can quickly understand the data., Weight: 0.15652820602 Pounds, Manufacturer: Xnuiasqe