Harry Bloomfield wrote:

ARW wrote:

https://www.bgelectrical.uk/wifi-sockets

I think those wifi sockets use mains signalling,

From their FAQ

"How does a Wi-Fi range extender socket work?

By positioning the Wi-Fi socket halfway between your router and the area
of poor reception, the range extender will relay the signal to further
spread coverage."

which implies it's a wifi repeater, not a powerline device