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 with compliant headsets. 4 Pole connectors are also called "TRRS" connectors because they have 4 sections on the connector Tip Ring Ring Sleeve. These sections are separated by 3 black rings. 4 Pole 3.5mm Stereo Plug 4 Pole 3.5mm Stereo Socket Extends earphones and mic Tip Ring Ring Sleeve Connectors Gold Connectors Black PVC Jacket