single brush head can be used for 6-12 months (this set is also equipped with a replaceable brush head). ^The number of bristles has been increased from 768 in the third generation to 1908. In order to improve brushing and massage the gums, the external test has also added a brush head. ^Four modes at the touch of a button: A. Strong mode, powerful brushing; B. Medium mode, comfortable brushing; C. Gum massage mode; D. Whitening mode for teeth whitening. This U-shaped toothbrush only requires you to bite it gently and then swing left and right to clean your teeth 360 degrees. ^Gently bite the brush head and use the sonic wave vibrations to clean your teeth in an all-round way. You can put on makeup while brushing your teeth or getting dressed. ^This electric toothbrush makes your morning routine more efficient. When you use the blue light whitening mode, you can completely free your hands.