This is a replacement cable that connects from the Plantronics wireless headset base (ie CS55, CS70, CS70N, CS351, CS361, etc) to your office phone. The black cord has two modular plug on both ends. 50cm in length.  part# 65111-01

Note: if you have the Plantronics CS50, Avaya AWH-55+, or AWH-54, we recommend the dual filtered cable instead: part# 66291-01.  Otherwise it may cause buzzing in the headset or telephone receiver.