Corinex Powerphase Coupler Model D4
By Corinex

4 Pin Dryer Coupler - When the outlets in just one room or section of your house have a noticeably weak Powerline network connection, it may mean that those rooms are on a different circuit. The Corinex PowerPhase Coupler joins together the Powerline network frequencies from separate circuits. Simply plug in the coupler to extend your Powerline signal to the adjoining circuits. ... 

Corinex Powerphase Coupler Model D3
By Corinex

3 Pin Dryer Coupler - When the outlets in just one room or section of your house have a noticeably weak Powerline network connection, it may mean that those rooms are on a different circuit. The Corinex PowerPhase Coupler joins together the Powerline network frequencies from separate circuits. Simply plug in the coupler to extend your Powerline signal to the adjoining circuits. ...