Kanex recently announced two new external battery backups. The batteries have USB charging ports, which makes them suitable for a wide range of mobile devices and accessories.
Two models were announced with a dual USB charging ports and different capacities. The GoPower has a 1 amp and 2.1 amp outputs, with the higher intended for faster iPad charging. Capacities are 6,000 mAh, which should give 2 full charges on an iPhone 5s/5c and 11,000 mAh which should provide around four full charges. Weight the batteries are about 8 and 11 ounces, respectively.
Pricing is $49.95 on the 6,000 and no pricing is currently available on the 11,000 mAh model.