The actual specs do vary a bit. There was (is) a _huge_ thread about replacement batteries for the Palm Tungsten T3 over at Brighthand, last I checked (a year or more ago) it was some 90 pages.

Because of little available room in the T3 (not to mention that the original battery is hardwired in), after lots of research we ended up with a very small selection of possible replacement batteries. And because of the huge interest and that a few enterprising individuals went ahead and procured and prepared lots of batteries we had the possibility to compare performances. A standardized battery measurement test was developed, and the net result was that the actual capacity seemed to vary up to some 20% or more, IIRC. Some people would measure nearly 6 hours, for example, others just above 4. The battery I tested was around 4.5 hours. And this was from a big batch of batteries bought directly from the Korean vendor.

(Something else: We found that the same battery that our resident mod'ders procured was sold from different resellers, sometimes under different brand names, and it was advertised from everything between 1100mAh to 1500mAh. From what we could figure the real capacity would be something between 1050mAh and 1250-1300 mAh or thereabouts. Certainly 1500mAh was greatly exaggerated.)

(My memory may not be entirely accurate though, so for those who want to check the gargantum thread about batteries for themselves, here's a link: http://forum.brighthand.com/showthread.php?t=74036
110 pages.. with my configuration.)