Instruct: Classify Amazon reviews into positive or negative sentiment
Query: doesn't last - water gets in

This would be a good tooth brush had they designed it better. Water gets inside and stops it from vibrating. Some times I have to take the top off and separate it from the bottom for a few hours for it to dry out, to get it to work. Also, gunk builds up inside of it and looks pure disgusting after a few months. I've had this about 7 months now and I'm tossing it in the trash.