Quality Material:Telephone line coupler use high-quality PVC internal insulation, oxygen-free copper conductor,contact terminals, high-fidelity design | High Quality: Telephone line coupler has high-quality sound quality, exquisite workmanship, strong anti-interference ability and low signal attenuationcoefficient, accurate signal transmission,no static or distortion of voices | Wide Usage: Telephone line coupler compatible with all RJ11 devices,wide use to family, study, living room, bedroom, office, business meeting, education, entertainment, etc | Smooth connection:RJ11 inline coupler is used to connect and extend two existing telephone lines,easy to use, convenient connection | Product After-sales: If you are not satisfied with the telephone line coupler,you can contact us at any time, and we will serve you wholeheartedly