Review (1/5): Beware
Just bought my second unit because the first one did not last and finally died of corrosion. The new unit started acting up after two weeks. The problem is that the brush head and battery compartment do not have a waterproof seal. Water or worse gets in and corrodes and the unit stops working. Leave it for more than a couple of days without cleaning and drying inside and you will have some very slimy growth. Be sure to look at the customer photos supplied for this product ...The leakage and corrosion is exactly what to expect in a very short time.
UPDATE 9/8/2013
Despite extreme care to keep unit dry, water gets in and corrodes.
Finally contacted Philips after having two fail in less than a year. No problem they said they will send me a replacement. But it is the base and stand of a plug in model they are sending -- THEY NO LONGER OFFER THIS BATTERY MODEL