It's the 7600mAh/84Wh, model name WJ5R2. You'll hardly find a brand new original, but there are replacements on Amazon, AliExpress, and dedicated battery sites. They do sometimes put 4F5YV name besides WJ5R2 like they are the same battery but they are only compatible with the same devices and the 4F5YV has smaller 63 WHr capacity. Anyway it's questionable whether the 3rd party WJ5R2 offer the same battery life as the original and that depends on the particular replacement battery quality.