1. Ultrasound cannot be directly seen with the naked eye, but the indirect effects it produces when acting on a medium are observable. Many people mistakenly believe that "the bubbles or fluctuations seen are ultrasound itself," which actually confuses "ultrasound itself" with "the phenomena caused by ultrasound."

2. The adsorption effect of the suction cup is first and foremost closely related to the surface it is used on. Priority should be given to smooth, clean, and dry surfaces (such as glass, ceramic tiles, etc.). Before use, wipe both the surface and the contact area of the suction cup clean, then press the suction cup firmly to completely expel the internal air—this lays a good foundation for adsorption. Additionally, considering the product's high-frequency vibration characteristic during operation, this vibration may slightly affect the adsorption stability of the suction cup and cause a slight reduction in adsorption force. Therefore, if necessary during operation, you can use your hand to provide a little support to help the suction cup stay stable.

3. The product is specially designed with a safety protection mechanism. To avoid potential safety risks such as circuit load and unstable current during charging, the product is indeed set to be unstartable while charging. It can only be started normally after being fully charged and disconnected from the power supply. This is not a product malfunction but a consideration to ensure safety during use. You can pay attention to the status of the indicator light while charging (usually, there will be a light change prompt when fully charged). After it is fully charged, disconnect the power supply, then press the start button to try—usually, it can be used normally.