C2G RJ12 6-pin Modular Inline Coupler Straight-Through Beige

Designed to connect two modular cables together
If you are trying to link several line cords together, or extending existing modular cable runs, Cables To Go's In-line Modular Couplers can help you make the right connection. The in-line coupler provides a female-to-female feed-through connection for easy cable hook-up.