This convenient, ultra-compact and powerful portable battery box allows you to remain charged on the go. The luxury 4000mAh rechargeable, polymer battery box and USB cable can charge most smartphones twice and is reliable and safe to use. Whether at a festival, travelling, or in the great outdoors, this charger pack is a reliable companion whenever you need to charge your mobile devices. Charging time is approximately 6 hours. Lightweight and ultra-slim, it fits easily in your pocket or bag.