Griffin Technology Journi Portable Speaker for iPod Two 50mm high/mid-range drivers and two 64mm passive radiators use SRS WOW digital technology to expand the audio image 8-10 hours of play on a single charge via AC adapter or powered USB port Sync iPod with your computer's iTunes library as it charges Charges on AC power or through any powered USB port Adjustable dock connector for use with all iPod models with dock connection