Exchangeable Battery for iPhone 6S+/6+, iPhone 6S/6?
Amazon.com: SHENMZ Upgrade Battery for iPhone 6S, [3200mAh] Conqto 2022 New Version 0 Cycle Ultra High Capacity Battery Replacement for iPhone 6S Model A1633,A1688,A1700, No Tools : Cell Phones & Accessories
The iPhone 6s has a smaller battery capacity, but same battery life as iPhone 6, according to Apple - 9to5Mac
Battery Life and Charge Time - The Apple iPhone 6s and iPhone 6s Plus Review
Amazon.com: LCLEBM Battery for iPhone 6S Plus 4500mAh, New 0 Cycle Higher Capacity Li-ion Polymer Battery Replacement for iPhone 6S Plus - No Tools : Cell Phones & Accessories
Mobile Phone Battery For Iphone 6s Real Capacity 1725mah 3.8v Battery For Iphone 6s With Repair Tools Kit - Mobile Phone Batteries - AliExpress