E-paper or electronic paper (also called EPD: Electronic Paper Display) are display devices that reflect light just like ink on paper.
E-papers are perfect displays since the image remains fixed even after the power is switched off, thus consuming extremely low energy.
The present-day e-paper is based on the e-ink technology. E-ink technology consists of millions of tiny ink capsules filled with tiny particles, with the particles inside these capsules having different colors and different electric charges. When an electric field is applied, the charged coloured particles will move either to the top or bottom depending upon the polarity of the applied field and cause the surface of the e-paper to display text or an image by changing in color.
This one here is a 2" mono ePaper display with the resolution is 172×72 dots. The display provides 4 grey scales. It comes ready equipped with SPI interface and 3.3 V power supply.