i am fortunate to have a Nokia 6303 classic mobile, this has a standard 3.5 mm stereo headphone plug which fits nicely with the aux socket. The phone has voice command function. What this allows me to do is use my phone hands free with the audio coming over the built in speakers, i do not need to position my mobile close to my mouth as its microphone picks up my voice when the phone is sat in the tray next to the socket. No need for an expense hand free kit.