keyestudio 2004 I2C Module is a 20 character by 2 line LCD display with Blue background and White backlight. The original 2004 LCD needs 7 IO ports to be up and running, ours is built with Arduino IIC/I2C interface, saving you 5 IO ports. This LCD is ready-to-use because it is compatible with the Arduino Liquid Crystal Library.
The new OLED technology only uses electricity per pixel. Because each pixel creates its own light, only the pixels that are on use electricity. This makes OLED technology very efficient; also, the way these types of OLEDs are built allows them to be very thin compared to LCD.