A push-button socket is fixedly installed on the wall face of the housing. A compress push button with the extruding ink sheet is arranged on the push-button socket by a compression spring.

The epaper sheet, which uses the same e-Ink technology found in the Amazon Kindle ereader, is just millimetres thick and can be used to make phone calls, read ebooks and play music.

A positive charge applied on the top surface of the ink will allow the white to show, making the surface as white as a sheet of paper.