Got a set of these and they are working well as light switches, I can see into the rooms they cover so I know if they are on or off.
There is one button for each light, press on, press off but if you cant see the light then you will not know for sure if it is off or on as sometimes as with all remotes it doesnt register.
I do find them useful and so far they have worked flawlessly, the fact that there is an on/off switch on the plug itself is useful too, especially if there wasnt one before, i.e. plugged into an extension cord.
These use a radio remote, not infrared so work through average walls, maybe not so well in the castle though :)