PoweraddDirect via Amazon offers the Poweradd Pilot 2GS 10,000mAh Dual USB External Battery Pack in Silver for $21.99. Coupon code "II2XMTJA" drops it to $15.99. Plus, Prime members get free shipping. (Non-Prime members can spend $35 or more to bag free shipping; otherwise, it adds $6.52.) That's a buck under our mention from two weeks ago and the lowest total price we could find now by $11. It features two USB ports and a microUSB port, microUSB cable, and compatibility with most smartphones and tablets.