Amazon.com: Battery Case for iPhone 6 Plus / 7 Plus / 8 Plus, 8500mAh Portable Battery Pack Rechargeable Protective Smart Battery Case for iPhone 6 Plus / 7 Plus / 8 Plus
Apple Smart Battery Case for iPhone 6S review: Apple's answer to iPhone battery life: Slap a case on it - CNET
Review: Weak battery aside, Apple's iPhone 6s Smart Battery Case isn't as dumb as it looks - 9to5Mac
Move over Mophie, Apple has a $99 Smart Battery Case | Engadget