To be truly seamless, some interior design concepts need switches to be as invisible as possible. Until now full-flat switches that could satisfy this need have been limited to luxurious electronic switches and lighting control systems. ZENcelo switches, with the patented mechanism of "impress", enable electro-mechanical switches to achieve the same full-flat form factor, in a slim profile at an affordable price. In delivering on this promise, ZENcelo even features a clever mechanical devices called "Ondicator" to tell if such a switch is on or off.