Apple says iPhone 6s and 6s Plus battery life may vary 2-3% regardless of Samsung or TSMC chip - 9to5Mac
iPhone 6 Plus Battery (OEM Original)
Apple extends iPhone 6 battery life with rechargeable case
iPhone 6 Battery
Amazon.com: iPhone 6/6s/7/8/SE Battery Case Upgraded [6000mAh] Protective Portable Charging Case Rechargeable Extended Battery Pack for Apple iPhone 6 /6s/7/8/SE (4.7') - Black : Cell Phones & Accessories
Amazon.com: Battery Case for iPhone 6s Plus/6 Plus/7 Plus/8 Plus 8500mAh, Rechargeable Charging Case for iPhone 6Plus Extended Battery Pack Charger Apple 6s Plus Portable Power Bank Cover for 7Plus 8Plus (5.5”) :
Apple Smart Battery Case for iPhone 6 or 6S (hands-on pictures) - CNET
Atomic S Battery Case for iPhone 6 6S 4.7″ – [White / Silver]
Apple unveils official 25-hour battery case for the iPhone 6 and 6S - The Verge
Apple iPhone 6 Battery Replacement - RIS11109 at Batteries Plus
iPhone 6 Battery (OEM Original)
Battery for iPhone 6 Plus | Replace iPhone 6 Plus Battery
Apple iPhone 6S Battery Original 1715mAh with Warranty – Virateck
Apple iPhone 6 Plus – Battery Replacment – Proxell Technologies
Review: Apple Smart Battery Case for iPhone 6 & 6s | AppleInsider
iPhone Battery and Performance - Apple Support
iPhone 6s Battery Pack Doubles As Protective Case
Apple launches battery case for iPhone 6 & 6s: Digital Photography Review