Feature: 1. Smart Monitor: Able to better monitor the single phase over voltage and under voltage errors in real time to protecting the circuit. 2. Higher Safety: With 300-490V AC wide working range and high accuracy, the over under voltage protector enables good electrical safety. 3. Reliable Work: The automatic recognition on AC and DC voltage requires no switching, while the auto resetting makes operation easier. 4. Clear Display: LCD digital display can clearly show the voltage value, error status and setting parameters, very simple and reliable. 5. Easy to Install: Modular structure together with compact size and light weight will bring more convenience to the rail installation. Specification: Item Type: Over Under Voltage Protector Model: STVP-931 Material: ABS Rated Supply Voltage: 380VAC Working Range: 300~490VAC Working Frequency: 50Hz Voltage Hysteresis: 10V Asymmetric Hysteresis: 2% Automatic Reset Time: 1.5s Phase Loss Tripping Time: 1s Measurement Error: ≤1% with adjustable voltage range. Protection Class: IP20 Working Environment: -25~65℃, ≤85%RH, non condensing. Mechanical Durability: 1,000,000 cycles. Dielectric Strength: >2kVAC 1min. Package List: 1 x Over Under Voltage Protector1 x User Manual