Very hard to find:
RETAIL open-boxed Thinkpad replacement battery for i Series laptops. This is IBM part number 02K6576 and is also compatible with IBM part numbers 02K6577 and 02K6578.
Unlike most laptop battery replacements you find on eBay, this is a retail boxed version. Most of the batteries on eBay are mystery OEM replacements and/or pulls from who-knows-where. This, in contrast, is a genuine IBM part, sold at retail. These are very hard to find, even on the web (where most of what you find is also OEM replacements).
This was a customer return to a famous retail store. As is common, the customer purchased the wrong part number, which didn't fit their laptop. The store took it back. It has likely never been used. The battery serial number has been checked and matches the serial number on the outer UPC.
Because this is a retail IBM part, it includes the proper bezel at the end of the battery. Many of the cheap OEM batteries available on eBay do not include this bezel (seee photo), and finding a replacement is nearly impossible.
This battery fits laptops with IBM part number (see bottom of laptop) in the "2611-xxxx" series. It does not fit laptops in the "2621-xxxx" series.
Compatible laptops include: