Would you recommend this battery for T400?

[Think43p]

Not sure which one to buy. Im concerned about the manufacturer and cells used.

https://www.amazon.de/gp/product/B06XSV ... 9IIB&psc=1
Might go for either the 6 or 9

Or this:
https://www.amazon.de/PATONA-Laptop-Akk ... ERZ89V9Q55

Any input is appreciated. Thanks.

[Thinkpad4by3]

Both are knockoffs and really should be avoided if possible. The cells are surely going to be complete garbage, and especially given its a power hungry T400, your at the draw of a lottery to see if you get even a half-usable battery. Get yourself an OEM one and save yourself the hassle.

[Think43p]

Thanks for the tip however I searched and was unable to find an original lenovo battery seller.

Any recommended sellers that you know of in the EU zone?

[Pokrzept]

I'd recommend you to look for one with MITSU label on it. And in regard to the knockoff argument - most of newly produced non-OEM products will be at least as good as 10 year old OEM one.