Product Details： 1. 9 Inch Nfc-powered E-paper.adopts Novel Passive Nfc Technology. No Battery Required, No More Battery Life Trouble. App Is Provided,easy To Use. Protective Abs Case,nice Light Weight. Wireless Nfc-powered Display Refreshing,passive Nfc Solution, No Battery Required, No Messy Wiring, Stable Operation How It Works: To Refresh The Display Content, Use A Smart Phone With Nfc Function, Or An Nfc Reader, Close To The E-paper For Both Wireless Powering And Data Transfer. Refreshing Example: Refreshed By Smartphone, Comes With Android App, As Easy As Swiping A Credit Card. Refreshed By St25r3911b Nfc Board. Power Supply :wireless . Grey Scale : 2. Display Color : Black / White . Refresh Time : 2s (data Transfer Time Is Not Included). Dot Pitch : 0.138x0.138 . Display Size: 66.89mmx29.05mm. Resolution : 296x128 . Outline Dimension : 87.5mmx47.7mm. Viewing Angle : 170. Application Examples: Suitable For Price Tags, Asset/equipment Tags, Shelf Labels, Conference Name Tags Resources . Size: 87.5mm X 47.7mm Mate