This button is a three-way switch; it highlights items that are bound to the data model, items that are not bound to the data model, or no items.

They were approached by psychologists at three US universities searching for a way to switch the apparent gender of volunteers talking to each other through video conference software.

Voltage detect of three phase AC, the warning of over-voltage, under-voltage, lost phase and power failure, two-way AC circuits switch full-automatically.