It is unbelievable that a normal looking Hi-Fun backpack can be transformed into a beach towel that comes with speakers. Have a good and enjoyable day at the beach or swimming pool at the same time still can listen to your favorite mp3 music. The product is compatible with iPhone, iPod, mp3 player, and any other audio source through the universal 3.5 mm jack. With powerful speaker built into the inflatable pillow (removable to allow washing) and the large integrated lithium-ion battery, the battery is easily rechargeable via USB port, so hi-Fun play your music for hours. This versatile product indeed can be easily transformed back into a comfortable backpack.