LoHi via Amazon offers the LoHi 7,000mAh Battery Case for iPhone 8 Plus / 7 Plus / 6s Plus / 6 Plus in Black for $39.99. Coupon code "AVZQH662" cuts it to $24.79. With free shipping, that's $15 off and the lowest price we could find, although we saw it for a buck less six days ago. It can hold two full charges, features LED indicators, and adds 0.36" thickness to your iPhone. Deal ends December 10.