Monoprice 50ft 3.5mm Stereo Plug/Plug M/M Cable &ndash; Black (100647) The 3. 5mm (1/8") stereo TRS connector is more commonly known as the Headphone Jack on portable mp3 players and mobile phones This cable features a male 3. 5mm stereo (TRS) plug on each end with molded connector housings and strain relief boots The cable is ideal for connecting a stereo audio output such as an mp3 player or phone to a stereo audio input such as the auxiliary input on a car stereo system