The 2TT-102-4POLE is a 2 metre 4 pole 3.5mm TRRS extension cable. TRRS cables are usually found on mobile phones because they can carry two-way audio (headphone and mic) allowing you to make calls wit more→h compliant headsets. 4 Pole connectors are also called "TRRS" connectors because they have 4 sections on the connector, T ip, R ing, R ing, S leeve. These sections are separated by 3 black rings.