The box includes RS465 different lengths cables while the upgrade kit includes a power adapter + RS465 cable. If you purchase this box without the upgrade kit, you will need to purchase a power adapter separately. This box is a proprietary Creality hardware which won't work with any other Klipper printer. They implemented proprietary RS465 data exchange protocol between the box and the printer host.
It is all included but you still need the Creality upgrade kit K1 without which it does not work. you have to completely rebuild the printer. Here is a top guide https://www.youtube.com/watch Have fun