Andrea Communications C-100 Mobile Headset Adapter Cable with Dual Microphone and Speaker to Single 4-Pin Shared Audio Plug TRRS, 3.5mm Converts all Andrea Communications headsets with Dual 3.5mm Audio plugs into a single 3.5mm 4 conductor Plug For mobile phone use or for computers with a single Audio port Gold-plated connectors reduce corrosion and oxidation, improve signal quality, and help ensure maximum performance Compatible with all versions of iPhone, smart phones and most mobile phones, excluding Nokia Compatible with all laptops, notebooks, tablets, MacBook's, and e-readers using a single Audio port