This is a 20x4 2004 LCD Display Screen, can display 4 lines of characters, and each line can display 20 characters, used for Arduino UNO R3 Mega2560 Nano Raspberry pi. Note: The address of the IIC device is 0X27, and the device address can be modified by short-circuiting A0/A1/A2. For details, please refer to the data sheet. Feature: Supports I2C protocol. The backlight can be seted by jumper cap. When the jumper cap is connected, the backlight turns on. When removed, the backlight turn off. The contrast is adjustable with the blue potentiometer on the back. Clockwise rotation is enhanced and counterclockwise rotation is weakened. Specification of 2004 LCD: Model: LCD 2004A Dimensions: 98.0mm × 60.0mm Field size: 76.0mm × 26.0mm Point size: 0.55mm × 0.55mm Character size: 29.5mm × 47.5mm Working voltage: +5V/+3.3V Working temperature: -10～+60°C Storage temperature: -20 ~ +70 ° C Pin description GND ------ Ground VCC ------ power supply (5V or 3.3v power supply display is a little different) SDA ------ I2C data line SCL ------ I2C clock line Connection： Arduino UNO R3/Mini/Nano SDA ----> A4 SCL ----> A5 Arduino Mega 2560 SDA ----> 20 SCL ----> 21 Packing list: 20x4 2004 LCD Display Screen *1 PCS 4PIN DuPont line*1PCS Warranty: DSD TECH offers a 12-month warranty and lifetime technical support.