Specification: 1. Specially designed for ipod, iphone, mobile phone, but also MP3, MP4, laptop, PC and other audio players. 2. Patented expansile resonator will strengthen the sub-woofer output. It s easy to carry when closed. 3. With standard port which is compatible to ipodipone, and it also has 3.5mm audio 2.0 channel inputting. 4. Built-in rechargeable Li battery protected multiple circuits. The continuous working time is more than 6 hours. 5. With rising voltage circuit inside speaker, it can charge your ipod and iphone with this function.