I bought a new iPhone 8 plus battery from another online replacement parts store, I didn't know the exact reason behind it, but the battery would completely drain after using it for 23 days. The mistake I made was not seeing the reviews before purchasing this battery from that store. I searched again online and noticed phonepartworld was selling brand new batteries with good offers on their site at that time and I quickly placed the iPhone 8 plus battery order and received it with absolutely no issues, it was a genuine battery and brand new. Now after fitting in the new battery from phonepartworld, I haven't faced any issues with the product for the last couple of months. Strongly Recommend!