A vital tool for travellers & festival-goers, these portable battery banks aim to keep devices powering on with up to three full recharges packed into a lightweight aluminium case. The portable batteries are compatible with smartphones, MP3 players & other devices that charge via USB (Universal Serial Bus) or micro-USB connections. Portable charging device Compatible with smartphones & other devices that charge via USB (Universal Serial Bus) or micro-USB connection Charges devices in 90 minutes Up to three full battery back-ups 2200m Ah battery capacity Lightweight aluminium case