Ruiling 10M 30 Feet 3.5mm Jack Audio Stereo Earphone M/F Extension Cable Cord Male to Female 100% Brand New & High Quality 30Ft 3.5mm Stereo Audio Female to Male Extension Cable Cord For Mp4 Mp3 Mobile Phone The One End is 3.5mm male, the other end 3.5mm female, to connect the same kinds of headphone plug size. Whether listening to music, receive audition or for laboratory extension can be used.