usb charging only [SEP] got this thinking it would work better than brushing and flossing i would say it is about the same it is small so it would be convenient to bring with you on travels if you prefer over standard brushing i am not thrilled with the usb only charging option i want to be able to plug it in a standard outlet without having to get another adapter the water tank only lasts about a minute would prefer longer but of course that would increase the size of the product