AnkerDirect via Amazon offers its Anker PowerCore II 20000 20,000mAh 6-amp Portable Battery Pack for $43.99. Coupon code "ANK3USB2" cuts that to $33.49. Plus, Prime members bag free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $5.99.) That's $2 under our December mention, $57 off list, and the lowest price we've seen. It features three PowerIQ fast-charging USB ports and can be fully charged in just under six hours via its dual microUSB inputs. Fully charged, it can charge an iPhone 7 almost seven times, Galaxy S7 four times, and most tablets almost twice.