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. The 3. 5mm (1/8) stereo TRS connector is more commonly known as the Headphone Jack on portable mp3 players and mobile phones. Quality at a Fair Price: Monoprice's rugged design and rigid quality control standards deliver high quality products at fair prices.