By plugging in your headphones into the 3.5mm jack socket, you can then plug in your headphones into the other end to extend the cable as far as you want. Now you can switch on the TV or stereo and sit back and relax in your favourite chair across the room, or plug in some mini speakers and position them in various locations some distance away from the audio source to distribute the sound evenly. There is even a volume control integrated into the cable for convenience.
