Have you ever had experiences that devices are running out of battery while in use? It is disturbing when you are enjoying your games or chatting happily with friends on the phone. Powerocks Stone Power Bank (3,000 mAh) won't let these situations happen again. You can charge your devices in a flash before battery exhausts. You can charge your iPhone, iPod, Blackberry, HTC, many other kinds of smartphones, PMP, PSP, NDS, NDS Lite and any other applicable devices. Ultra convenient and tough wearing this device is a must for any one who is always on the go!