From hands-free to music in your ears! Listen to the music files on your compatible cell phone with this adapter and your headphones. Just plug the adapter into the hands-free jack on your phone, then plug your headphones into the other end of the adapter for great stereo sound. Let the tunes be heard! The adapter allows you to use common 2.5 mm devices such as headsets, earbuds and headsets with your unit's 3.5 mm accessory jack. Male End of the adapter is 3.5mm, Female End is 2.5mm.