Features: Automatically resets to prevent prolonged power outages, quickly response, and eliminate potential over voltage and under voltage dangers. Protector can effectively avoid damage to electrical equipment and machines caused by highly voltage at the moment of power on, and avoid damage to electrical equipment and machines caused by short term power on and close flashes. Overvoltage and undervoltage protections, voltage imbalance protections, phase fault and phase failure protections, overcurrent protections, automatic resets, and other multiple protections functions. The digital display displays the working voltage and current in real time, and current and voltage display is clear. Guide rail installation, making it easy and secure to install. This protector have quickly response speed and sensitive internal component. Specifications: Materials: Plastic Size: about 9x8x6.50cm/3.54x3.15x2.56inch Rate power supply voltage: AC230V Working voltage ranges: AC120-300 volt Rate frequency: 50/60Hz Asymmetrical delay: 10second Rate insulation voltage: 450W Output contact: 3NO Working temperature: -5~40 Note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to difference between different monitors, the picture may not reflect the actual color. Package includes: 1pc 3 Phase Din Rail Voltmeter Ammeter