iSymphony T-Speaker Portable Mini Speaker for iPods (Black) Tiny battery-operated stereo speaker for iPods and other audio devices Fits conveniently above 3.5 mm headphone port for on-the-go listening 300 Hz to 20 kHz frequency response; 26 mm mylar cone driver Compact size fits easily in shirt pocket, purse, or backpack sleeve Gold-tipped stereo plug; runs for up to 10 hours on 1 AA battery