Feature: 1. Due to new passive near field communication technology, this 7.5‑inch electronic ink screen supports no need of built‑in battery power consumption without trouble of battery life. 2. Simple mobile APP operation, high‑quality ABS shell, beautiful and thin, new passive near field communication technology wireless transmission can be supported while no battery environmental protection and energy saving. 3. Built to strict quality control standards with simple installtion, E‑ink screen is improved for more durability. 4. To work stably, this e‑ink screen keeps new passive near field communication wireless brushing technology adopting passive near field communication scheme, which is no need for built‑in battery and no cumbersome wiring. 5. Smartphones or card readers with near field communication function can be near this product to wirelessly power and makes the display content refreshed while the display needs to be refreshd. Specification: Item Type: E-ink screen Power Supply: Wireless power supply Gray Level: 2 Display Color: Black and white Refreshing Time: 5s (not including data transmission time) Dot Pitch: 0.205 x 0.204 Display Size: Approx. 163.2 x 97.92mm / 6.4 x 3.9in Resolution: 800 x 480 Viewing Angle: >170°. Package List: 1 x E-Ink Display