1Adopts new passive near field communication technology, such 2.13-inch electronic ink screen has no need of built-in battery power consumption, no trouble of battery life. 2Supports no battery environmental protection and energy saving and simple operation of mobile APP, this screen daopts new passive near field communication technology wireless transmission, which is beautiful and thin with high-quality ABS shell. 3To 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. 4E-ink display installation is simple, and its quality is guaranteed, you can use it with confidence. 5When you need to refresh the display, you can use near field communication enabled smartphones or card readers near this product to wirelessly power and refresh the display content.Item Type: E-ink screen Power Supply: Wireless power supply Gray Level: 2 Display Color: Black and white Refreshing Time: 2s (not including data transmission time) Dot Pitch: 0.194 x 0.194 Display Size: Approx. 49.7 x 21.75mm / 2 x 0.9in Resolution: 250 x122 Viewing Angle: >1701 x E-Ink Screen