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