Review on SunFounder I2C LCD Module Shield for Arduino R3 Mega2560 - 2004 20x4 Serial TWI by Marfel Fekete

Some things you should know about this LCD. The figures show the I2C interface board detached from the display. It doesn't come off. This forces you to use the LiquidCrystal_IC2.h and Wire.h libraries when used with an Arduino Uno/Mega/Nano. If your project uses the LiquidCrystal.h library and accesses LCD pins directly (ie: not I2C or TWI), choose a display that does not have an I2C interface. The picture shows the individual pins that are normally connected to the LCD interfaces (top edge of the display board), but you cannot directly attach/address them on this model. However, I2C/TWI is handy because you only need to use 4-wire connections for the board to work. These are +5V, GND, SDA and SCL. The trade-off is that the I2C/TWI interface is slower and may not be suitable for some applications where speed is important, such as B. an accurate speed display. I recommend this board but with the above considerations in mind. Also, although not listed, this also works with the Arduino Nano.