As one of its daily deals, newegg offers the UNU 14,000mAh Enerpak Extreme Dual USB External Battery Pack in Black, model no. UNU-EP-02-14000BS, for $54.99 with free shipping. That's $9 under the lowest total price we could find for any 14,000mAh external battery pack elsewhere. It's compatible with most smartphones and tablets and features 2.1-amp output and simultaneous dual charging. Deal ends today.