No backlight required, e-Paper keeps displaying the last content for a long time without power. It does not contain a power supply such as the battery itself, which is suitable for application environments with a limited power supply. You can modify the display content by smartphone. It is suitable to use as equipment labels, shelf labels, information storage, etc. Equipped with ABS plastic shell with good strength and toughness. Overview: This is an NFC-powered 1.54inch e-Paper Module, with 200 x 200 resolution. Users can transmit data from a smartphone or NFC reader to e-Paper and refresh by NFC. Suitable for mobile phone key ornaments, business cards, decorations, and other applications. Specifications: POWER SUPPLY: Wireless GREY SCALE: 2 DISPLAY COLOR: Red / Black / White REFRESH TIME: 8s (data transfer time is not included) DOT PITCH: 0.138 x 0.138 DISPLAY SIZE: 27.60mm x 27.60mm RESOLUTION: 200x200 OUTLINE DIMENSION: 47.84mm x 41.28mm VIEWING ANGLE: Greater than 170° Colour:White Material:Metal Package Contents: 1 * NFC Memory Keyring Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.