How many colors can be displayed on the screen?
- For 2.9/7.5-inch, it has black & white & red color built-in; or lack & white & yellow color built-in.
- For 4.2-inch, only black & white.
- Because more built-in color, the screen needs more time to respond and consumes more energy. 4.2-inch has 4 buttons as user input, it needs a faster refresh rate to change the screen content.