Hi, I'm Phil Lott with the costco.com buying staff. The Tweakers Lites mobile speaker is designed to best accommodate high fidelity sound reproduction demands. This speaker system is one of the best solutions for iPod, iPhone, or other portable electronic devices. Its 1.7 watts of stereo power offer bright highs that are enhanced with the exclusive twist-open pop up acoustic bass chamber. The Tweakers mobile speakers have a built-in amplifier ready at the touch of a button. The built-in rechargeable lithium ion battery provides hours of listening pleasure. The Tweakers come with an exclusive retractable charging cable that allows indefinite continuous play when connected to a power source. The magnetic coupling allows for easy storage. I'm Phil Lott, and the Tweakers Lites pocket sized speakers are available at costco.com.