X40 4-Cell battery in X41?

[Rax]

Does anyone know if the X40 batteries are compatible with the X41? Despite combing IBM.com, I can't seem to find out for sure. The pictures they show seem to suggest that they aren't the same...

The reason I'm asking is that I've got a new X41 that came with the extended 8-cell battery, and I'd like to grab a 4-cell just to shave some weight off for shorter trips. BUT, I can't seem to find any mention of a X41 4-cell battery.

Any ideas?

[bhtooefr]

http://www-131.ibm.com/webapp/wcs/store ... d=10000001

X40 SERIES is the key word there. Yes, it's compatible.