Great as a quick studio splitter or for airplane flights, waiting rooms or anywhere you're in the mood to share. Plugs into the mini-jack of any Camcorder, iPod, MP3, CD, portable DVD player or laptop computer. Allows two people to share any audio device with a 3.5mm jack. There's no sacrifice to sound and there's separate volume control. It can also be used with a phone, such as an iPhone, to allow you to use a microphone on one side and a headphone on the other.