The Wicked Audio Divvy is an audio splitter designed so two people can listen to the same iPod, smartphone or tablet, with each having an independent volume control.
The device is pocket-sized and will work with most devices. There’s no setup. Just plug in the single 3.5 mm end into a headphone port and start listening at your comfortable volume levels.
There are no batteries or recharging; it works on its own from the output of your audio source. $10 at www.wickedaudio.com