Features: With two station designs (commonly used for A and standbys for B), suitable for systems with 50-60hz and rate current 63A. The Switches is mainly used for testing whether normal or spare power is normal or not.It can Switches power supply in 20ms to build uninterruptible power supply. When the normal power is abnormal,the spare power work at once,which therefore ensures the continuirty,reliability,and safety of power supply. When the normal power supply is normal,it will automatically switches back from the backups power to the normal power supply. Specially designs for household Din Rail installation. Convenient in instabllation and maintenance. Specifications: Materials: Plastic Voltages: 110V/220V (optional) Width: about 102mm/4.02inch Number of poles: 4P Rate working current: 63A Rate frequency: 50-60HZ Conversion action time: 20ms Rate insulation voltage: 690V Can bear maximums pulse voltage: 8KV Package Includes: 1pc Double Power Automatic Transfer Switches 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.