@Apie77 

Hello, it should be Deco P7 or Deco M9 plus. First you can use them to boost the wifi signal and build up a mesh wifi system. The Deco units can connect to each other by wired cable and wireless and they support access point mode and regular wireless router both, but the main Deco need connect to the internet source/router by wired cable. 

Except the Deco, there are some network expansion devices, like range extender and powerline adapters. The range extender can connect to the C3150 by wireless to boost the wifi signal, while the powerline units have a kit, the main adapter connects to the main router by wired cable, and the extender unit can be located after you paired them, they will comminucate with each other via powerline. 

Note: The performance of the range extender relates to the wireless interference, like distance, obstacles, while powerline adapters relates to the powerline environment. 

May it help and have a good day.