Just as the name of the gadgets company, the portable USB battery charger is actually an useful thing.
From the images, we can clearly see it’s an unique portable charger, which comes with an USB port. Apparently the USB battery charger can offer power for a pair of rechargeable batteries via USB port. According to the instruction, two AA batteries will be fully charged in about 4 to 6 hours. Moreover, the USB battery charger ships with two AA rechargeable batteries.
The portable USB battery charger is priced at $20.95 USD. If you’re interested, you can get more details from Useful Things.
Additionally, if you like more portable USB charger, you would like to check this USB rechargeable battery.
Portable USB Battery Charger Source