Is this toothbrush waterproof? Can I take it into the shower and use it there? Thank you

The battery lasts almost 3 weeks for me. I usually need more than 2 minutes, twice a day.

If I stick to the built-in timer (the toothbrush switches off automatically after 2 minutes), I can brush my teeth at least 25 times.

With the included case, I can charge the toothbrush on a USB charger when I am out and about. This works well with a mobile phone charger, as the mobile phone also needs to be charged regularly (usually daily).

From this point of view, I find the built-in battery more than sufficient. I would buy the toothbrush again at any time.