Amazon.com: New Replacement BLP657 Battery Compatible with OnePlus 6 1+6 A6003 with Tool : Cell Phones & Accessories
Oneplus 7Pro) After 3 years I finally replaced my back and battery!! Total $25. It was tough but really fun process to do. Took about 30minutes. The battery health was around 78%
Amazon.com: for 1+ One Plus 3 A3003 Replacement Battery BLP613 Free Adhesive Tool : Cell Phones & Accessories