Gefen's powerline filter allows you to eliminate 'noise' on your powerline network caused by other devices plugged into sockets that are connected to the powerline network.
How This Works
Devices on your powerline network (when the existing powerline in a building is used for networking, video streaming, etc) can cause 'noise' which causes interference, leading to slower data transfers and artifacts in video. When the devices plugged into your powerline network go through this filter, it eliminates the noise. Use a power strip to get multiple devices going through this filter.
You can also use this filter to diagnose which devices are causing the noise. Devices that use a lot of power like vacuums and hair dryers cause the most noise, while devices like phone chargers and lamps probably won't cause noticeable interference.