Each module has a button on the side so you can manually cycle it on or off
The modules accept (and plug into) three prong grounded plugs.
Works great. Just put fresh batteries in. I used them for my shop lights but I upgraded to a set that has five modules. (I’m getting older and need lots of light. )
I suppose you could put Christmas lights, or a radio, or anything that would be useful to remotely turn on and off. I used these for my fan and my air filter as well.