Cassette recorders incorporating radios; cellular radio telephone apparatus; combined radio and cassette tape players; electronic radio apparatus; music centres incorporating radio and television receivers; portable radios; radio control apparatus; headphones; headphones for audio apparatus; headphones for microphones; stereo headphones; stereo headphones for personal entertainment use; stereophonic apparatus incorporating headphones for personal use; stereophonic headphones; digital music (downloadable) provided from MP3 web sites on the Internet; MP3 players