SilverCon Creative Mini Balloon 3.5mm Music Speaker Sponge + ABS USB Travel Speaker for Mp3 Mp4 Cellphone Laptop (Black) with FREE SilverCon Universal Cable Tie Ultra Portable mini speaker Build-in Rechargeable battery lasts up to 6 hours of continuous use. Audio dock could be charged in PC with USB cable, or by a charger. Battery can be used repeatedly for about 500 times.