This RJ22 4-pin Male Connector is usually the standard plug for telephone headsets and handsets but can easily be repurposed for all kinds of 4 conductor applications.
This clear polycarbonate plug with 4 conductor wire is approximately 18" long (combined length). This plug is also called by common names such as RJ9, RJ10, & 4P4C. Double your fun with the mate to this plug: the RJ22 4-pin Female Right-angle connector. Use this plug/receptacle combo in applications where 4 conductors are needed.