I bought this battery pack thinking (and this was in the advertising) that the battery fits in a E2 Tungsten, but it didn't! Due to I was outside US, returning will be more expensive than the purchase... Wrong advertising...

The battery with tools arrived promptly. I actually received a stronger battery than what I ordered (1350 mAh instead of 1000 mAh). I contacted the company (The Battery Center) to make sure that the battery was compatible with my Palm E1. They responded promptly that not only was the battery compatible, that I would get more use out of each recharge.

As many others have noted in the reviews of the the battery itself (sold separately without the tools) HQRP 1000mAh Internal Li-Polymer Replacement Battery for Palm Tungsten E T5 TX PalmOne PDA, the installation itself into the Palm unit is not for the faint-hearted or technically impaired. The battery replacement includes opening up the unit, removing the board without losing the on/off button and top piece, prying the old battery off the board, and soldering in the new battery.

I found the video:
http://youtube.com/watch?v=JkF9ex8ZDCU
to be of tremendous help in knowing what to do.

I actually accidentally broke the internal on/off switch off the the motherboard, but was able to carefully resolder it in place, and put the unit back together. Once successfully put back together, the Palm unit (which was totally dead) works great again.

This is not a wise choice. It is virtually impossible to install this battery because the wire guage on the battery is too large to fit into the old connector and the battery does not come with a compatible connector. Save your money and use to simply buy a new Palm pilot.