1Monitor the working voltage (true RMS measurement). 2The operating mode can be selected via the rotary knob. 3High accuracy, voltage measurement accuracy is 1%. 4The working status of the relay is indicated by the LED indicator, which is simple and convenient. 5Compact size, only 18mm width, 35mm rail mounting.Features: 1. Monitor the working voltage (true RMS measurement). 2. The operating mode can be selected via the rotary knob. 3. High accuracy, voltage measurement accuracy is 1%. 4. The working status of the relay is indicated by the LED indicator, which is simple and convenient. 5. Compact size, only 18mm width, 35mm rail mounting. 6. Apply to over voltage protection for electrical equipment or compressors, emergency/backup power switching control. Specification: Function Voltage monitoring Power terminal (monitoring terminal) A1-A2 Rated power supply voltage (Optional) 1: AC220V 2: DC12V 3: AC/DC24V-48V 4: AC/DC110V-240V Rated power frequency 45Hz-65Hz Rated insulation voltage 460V Hysteresis value 5%-20% Power indicator