TP-Link TL-PA4010 Powerline Adapter (New Marston OX3)
One TL-PA4010 Powerline Adapter. I think it is this model: https://www.tp-link.com/us/home-networking/powerline/tl-pa4010/ I guess you will need two of them to use it: you connect your router to one, a device to the other, and plug both into the mains, which they use for a connection.
This offer has been gifted to someone and is no longer available.