Review on 120PCS 10CM Dupont Wire Male to Female Breadboard Jumper Wires - 3 Inch Length by Maili Silcox

They are needed if you want to connect your 3D printer to the ELEGOO UNO R3 Board ATmega328P ATMEGA16U2. , you will need both items, and both worked without problems the first time. It's that simple. It's like having the right tools in a box in case something goes wrong. If you are flashing your printer's firmware, you must have these two items. Otherwise, wait for them to come to your house so you can set up the printer properly. Otherwise there is not much to say about cables. They worked. They were packed pretty well, what else do we need?