1. This relay can monitor own working voltage (true measurement). 2. 8 kinds of adjustable rated voltage. 3. Voltage measurement accuracy is not more than 1 percent . 4. Relay working status is indicated by LED indicators. 5. With super small volume, this relay can be mounted on 35mm DIN rail. Application: Equipment protection and control(tower , elevator, agriculture equipment, refrigerated trucks) equipment from reverse running Normal or emergency power supply switch against phase failure of a dynamic load. Function: Monitor L-L voltage (3-phase 3-wire system) Monitoring terminal: L1-L2-L3 Power: L1-L2 Rated working voltage: 220-230-240-380-400-415-440-460(P-P) Rated power frequency: 45Hz-65Hz Measuring range: 176V-552V Voltage range: 2 percent -20 percent (rated voltage) Voltage fixed rate: 2 percent Voltage measurement error: less than 1 percent Power-on delay time: 0.5s Knob setting accuracy: 10 percent Reset time: 1s Temperature fluctuation error: 0.05 percent or C, at=20C Output: 1 x SPDT 10A or AC1 250VAC or 24VDC Minimum switching power: 500mW Overvoltage: 2 percent -20 percent Undervoltage: -20 percent -2 percent Action delay time: 0.1-10s adjustable Phase sequence protection: Yes Phase failure protection: Yes Power indicator: Green LED Output relay indication: Red LED Mechanical life: 1x107 Mounting : 35mm DIN rail mounting Mount altitude: less than 2000m Weight: . 78g or 2.7oz size:95x18x64mm colour:white Material:plastic Package Contents: 1 x Voltage Monitoring Relay 1 x Instructions Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is 1-3cm.