Stop walking across a dark room to turn on the light. Install a 3-way switch and control lights from two locations.

Belkin today announced a new addition to its lineup of HomeKit-compatible Wemo-branded smart devices, the Wemo 3-Way Light Switch, which is now available. Announced at CES, the new 3-Way Light ...

Or flip a switch at the bottom of the stairs, and then again at the top. The next person, coming from either direction, must be able to turn the light on again. That's where 3-way switches come in.