Upbeat Audio T794 Boosteroo with USB Connection and AC Adaptor for PC and Audio Applications Designed For Connecting Phone To Modular Jack Separates Audio Signal Into Individual Stereo Channels To Drive 3 Separate Headsets Or Speakers Solves The Problem Of Low Volume From Personal Portables, Including Mp3 Players, Pocket Pc'S, Laptops, Portable Dvd Players, Cd & Tape Players Includes Usb Connection & Ac Adapter