Headphone adapter splits the audio/sound into five 3.5mm ports. Each port can be output end or input end. Reverse basic qperation (tested):like a music mixer, You may input 2,3,4,up to 5 audio inputs (like computer, hi-fi, music player...etc) and 1 output audio (like headphone, earphone, speaker. etc). Connect up to five headphones to one device for sharing music with your friends and family. Small and lightweight, suitable for traveling, home, party, office, car and so on. This headphone splitter is a lifesaver for people trying to watch or listen to the same thing.