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. 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 Green LED Output relay indication Red LED Action delay time 0.1s-10s, 10% Voltage measurement error ≤1% Power-on delay time 0.5s Knob setting accuracy 1% Reset time 1s Temperature fluctuation error 0.05%/°C, at=20°C Output 1 * SPDT 10A/AC1 250VAC / 24VDC Minimum switching power 500mW Mechanical life 1 * 10000000 Electrical life (resistive load) 1 * 1000000 Working environment temperature -20°C- +55°C Storage and transportation ambient temperature -35°C- +75°C Installation method 35mm rail installation Protection level IP20 Installation location Any Installation altitude ≤2000m Pollution degree 2 Wiring ability 1 *  2.5mm2 or 2 *  1.5mm2 Dimensions 90mm * 18mm * 64mm / 3.5 * 0.7 * 2.5in (Approx.) Standard GB 14048.5 IEC/EN 60225-1 Package list: 1 * Relay 1 * User manual