Altec Lansing IM510 Speaker System Portable audio speakers use an advanced class D amplifier for maximum power Features superior technology for quality bass without a subwoofer, and a built-in docking station for transferring date and re-charging your Sansa MP3 Folds to close for convenient mobility; input jack so you can connect a second device, including CD, DVD, and other Sansa MP3 players Delivers more than 24 hours of battery life (four AA batteries not included) Dimensions 8.4 x 3.8 x 2.1 (WxHxD); weighs 1.25 pounds