1. Built-in screw wiring, safe and convenient to use, sturdy and stable structure, suitable for long time work
2. Can be used in electrical power, telecommunications, machine tools, shipping, textiles, printing, mining machinery and other industries signal indication, alarm signals, accident signals, etc
3. Professional and practical design, beautiful appearance, easy to carry and use
4. Made of plastic surface, durable and wear-resistant
5. No signal input prompt message: display 000
6. This product is prohibited in the frequency conversion, high frequency, inverter, harmonic interference signal strong power environment, applicable to sine wave 50-60HZ AC frequency utility power

Parameters:
1. Input voltage: AC 220V
2. Frequency test range: 3-120Hz
3. Accuracy: 2 percent +/-Hz
4. Display resolution: 1Hz
5. Sampling rate: about 1 time/s
6. Input circuit power consumption: less than 2VA
7. Ambient temperature: -25-55 degrees celsius
8. Overall dimensions: 73 x 73 x 52mm
9. Installation aperture: 68 x 68mm