Photos coming soon. The extended battery is a 2200 mAH battery (the standard battery is 1100 mAH). It's also double the size of the standard battery, so it doesn't actually fit in the Axim--it sticks out about 8 mm from the back of the Axim and comes with a special battery cover to cover the bulge. The Axim with extended battery won't fit in a standard case, so it comes in a set with a black aluminum case. It makes the Axim less comfortable to hold and more difficult to hold securely, and it also makes the Axim significantly bulkier--no carrying in a pants pocket.

The standard battery has more than enough juice to get most users through the day (about 3 hours of continuous use with over a week of standby time, depending on settings). However, if you think you'll need more power, the extended battery may be a good choice. It's also possible to get a second standard size battery (about 3x5 cm by 6 mm thick, about half the size of a small matchbox), charge it up, and keep it with you in case you ever need it. That might be the best thing if you're not sure you'll need extra power or will need it only occasionally; if you expect to need extra power regularly, then it makes more sense to get the extended battery.