1. Dual power Automatic fer switch can switch to Normal power or reserve power automatically. Please noted that the switch can't turn on or turn off the generator. This switch Normal power first. If normal power on, the switch will switch to Normal power. If normal power off, and reserve power on, the switch will switch to reserve power.2.WirePress the button to Automatic, the switch will switch to Normal power or reserve power automatically.Press the button to Manual, Then you have to switch the Direction manually.3. The Automatic fer Switch is terminal type automatic fer device. It's suitable for 3 phases 4 wires (or 1 phase 1 wire) dual power grid with AC 50/60Hz, rated voltage 230V and rated current up to 63A. When one power goes wrong (only test normal Phase A voltage and reserve Phase A voltage, only test loss voltage or loss phase),it will automatic connect one or several load circuits from one power to the other power automatically, to ensure normal power supply of load circuits. Rated voltage: AC230V 50/60HZNoted: power will be interrupted when Switching.Max current: 63A.Color: Grey+Black+BlueMaterial: PC plastic Package Contents:1 x Automatic fer Switch Only the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.