The BoomTube portable speakers are for use with MP3 players, CD players and computers. Two tweeters and two bass speakers are cleverly assembled in a cylindrical construction that protects the speakers while in transit. Quick to deploy and pack up, the tweeters use quarter-turn lock-ins as end caps to create a single, highly portable unit. The high perceived value and surprisingly low cost provide a significant margin, making it probably the biggest earning product for Virgin Electronics this year.