Hi,

FYI, all the TP-Link powerline adapters are compatible with each other. 

Considering the current one is TL-PA4020P, it is suggested to use 4 series, like TL-WPA4220, TL-PA4020/4010.

Besides, the model begins with TL-WPAXXX supports wifi function, while TL-PAXXXX does not. 

https://www.tp-link.com/en/home-networking/powerline/ 

Nice day. 

AndrewD wrote

I have a TL-PA4022P kit and want to get an additional power line adapter for elsewhere in our house and wanted to check which was the compatible one to buy