... -in Lin-ion 4.USB cable/remote control Features:This wireless laptop speakers can link to MP3, MP4, Notebook, CD, DVD, Mobile phone ... mobile & iPod, etc3)Stereo sound design, excellent ultra-low sound4)High-efficiency digital Amplifier, enjoy pure and beautyful music 5)Music ... : built-in Lithium rechargeable battery & USB power supply (5V, DC) wireless laptop speakers wireless laptop speakers