Here is how to find out if your iPhone 6s is eligible for a free battery replacement
Atomic S Battery Case for iPhone 6 Plus / iPhone 6S Plus 5.5″ – [Black / Black]
Apple iPhone 6S Plus Cell Phone Battery Replacement
How To: iPhone 6S Battery Replacement done in 2 minutes - YouTube
iPhone 6s Plus Battery Capacity Confirmed Smaller Than Predecessor
ClickAway Mobile Battery For Iphone Apple Iphone 6S battery - 1715 mAh Price in India - Buy ClickAway Mobile Battery For Iphone Apple Iphone 6S battery - 1715 mAh online at Flipkart.com
Apple will replace your iPhone 6, 6s, or 7 battery for $29 even if it's not being throttled
iPhone 6S Battery (OEM Original)
Amazon.com: SHENMZ Upgrade Battery for iPhone 6S, [3200mAh] Conqto 2023 New Version 0 Cycle Ultra High Capacity Battery Replacement for iPhone 6S Model A1633,A1688,A1700, No Tools : Cell Phones & Accessories