While most mobile devices use the 3. 5mm stereo headphone output most home audio systems with an amplifier or receiver use RCA jacks for audio inputs. This cable is ideal for connecting the output of your mp3 player or phone to your home audio system. It has a single 3. 5mm (1/8") TRS stereo male plug on one end and a pair of left/right RCA male plugs on the other end each with molded connector housings and strain relief boots