Quick installation - optimal efficiency
I connected the first one to the modem and then the second one to the second floor. I didn't need to synchronise them, it was done within 5 seconds and automatically.
It all depends on how your electrical wiring is set up but I did a test and it was as if I was connected to the modem.
It remains to be seen how stable it is but time will tell :)
In any case, I'm very happy with the product when I first discovered it and used it.