Which toothbrushes does this charger fit?

It is made for the Braun Oral-B electric toothbrushes named in the compatibility list for part 84848387. Check your handle's model against that list before buying, since not every Oral-B handle uses this base.

Does it replace the old tower charger?

Yes. It is the replacement for the older tower-style charger, part 67040023. Handles that charged on that tower are the ones this base is meant for.

Is a brush handle included?

No. This is the charging base only. You use it with a handle you already own.

Can I use it in another country?

The listing does not state voltage or plug type, so check the charger's label against your local mains before using it abroad. A voltage converter may be needed outside your home region.

Is it worth buying instead of a new toothbrush?

If your handle still works and only the charger failed, a replacement base keeps the brush going. If the handle itself is failing, a new toothbrush makes more sense.