describe: The number of bristles has increased from 768 in the third generation to 1908. In order to better brush teeth and massage gums, external testing also added a brush head. Four modes of one-key operation: A. Powerful mode, powerful brushing B. Moderate mode, comfortable to brush teeth C. Gum massage method D. Whitening mode for teeth whitening. With this U-shaped toothbrush, you only need to bite it gently and then swing it left and right to clean the toothbrush 360 degrees. Gently bite the brush head and use sonic vibrations to clean your teeth. Full range of teeth. You can brush your teeth while putting on makeup or getting dressed. This electric toothbrush will make your mornings more efficient. When you use blue light whitening mode, you can completely free your hands. Package contents: 1 piece toothbrush