I've been looking on ebay for an extra battery. I have found some, but I don't know whether they will fir in the T43p

Looking at the IBM site, T40/R50 series batteries are the same, but most sales on Ebay don't include the T43 as supported, max the T42. Are they incompatible, or are their descriptions not updated?
Example:
here
Do you guys have any experience with these cheaper units? Or would you avoid them, I wouldn't wanna see my T43p explode Nokia-like
Regards,
Gilles