4-Pin 3.5mm to dual 3-pin 3.5mm Headset Splitter Adapter features one 3.5mm Male and two 3.5mm Female connectors. Turns TRS audio plug and TRS microphone plug into one 3.5mm TRRS plug, allow you to use headphones freely on mobile phones or other devices which only have one 3.5mm TRRS port. Can be used with any portable device that uses a 4 position 3.5mm jack. Works great for recording smartphone conversation with the split audio cable connected to the recording device.Ideal for splitting audio for iPods, iPhones, iPad or any MP3/MP4 Media Players. Small design provide convenience for carrying, easy to use and intall.