Brand new and high quality. Best Design concept from the open source project NodeMCU The development board integrated 18650 charge and discharge system, comes with charge and discharge protection, while integrating an OLED and five-way button to facilitate the development. This item operation and NodeMCU consistent, an increase of a programmable LED, you can use GPIO16 to control, display 8266 running status and other functions. Integrated OLED and five-way button, more convenient development Five-way buttons are controlled by FLATH, RSET, D5, D6, D7, respectively OLED SDA and SCL, respectively, received D1 feet and D2 feet 5 digital pins can be configured separately for write / read / interrupt / pwm / I2C / one-wire supported 1 AD input Integrated 18650 battery charge and discharge system Micro USB input Arduino compatible NodeMCU compatible Wide voltage input range 5V ~ 12V 1 switch can control whether the 18650 power supply 1 programmable LED (D0) Charge protection Discharge protection