Features: Good function: The LCD with I2C port greatly enriches the human-computer interaction functions, and when they are connected to the controller, the controller without too many external ports will not occupy multiple IOs, and will not restrict other functions of the controller. It has only two bidirectional data lines, a serial data line and a serial clock. Specifications: Display: 2-lines x 16-characters Backlight: blue with white character color Four Pin Definition: GND, VCC, SDA, SCL Default I2C bus address: 0 x 3F for PCF8574AT chip, 0 x 27 for PCF8574T chip Working voltage:5V LCD controller: HD44780 Adjust Contrast: Potentiometer Adjust Backlight: Jumper Package includes: 4 x Blue LCD display 4 x I2 C serial interface Warm notes: The mention of brand names and any related models above is only for purposes of demonstrating compatibility, our brand name is Weewooday. Manual measurement, please allow slight errors on size, and the color might exist slightly difference due to different displays.