A pin flag switch can be viewed at Fromeco.org. basically it's a switch where the installation or removal of a metal wire opens and closes the switch. The only moving part of the switch is in your hand when it's on.

I kind of view a Voltwatch like I would a sundial. I know it's daytime 'cuz the sun is out, and it's sometime either before or after noon. Anything closer than that is guess work. Both are kind of pretty in the right setting.