Please use No.18650 Li-ion battery for the power supply, other batteries that voltage higher than 4.2V or lower than 3.7V are not allowed to use, otherwise the fan cannot work normally or get damaged. Please charge this product with 5V charger or the other 5V USB slots such as computer, portable power bank ect. Please do not charge with higher or lower voltage chargers. Please do not insert your fingers or other things into the protective screen to avoid damage to the fan blades or injury to your body. Please do not stop the fan blades on purpose, otherwise the motor of the fan will be burned out due to the over-current input. Please do not shake the fan violently to avoid any damages to the fan. It must be under audits guidance for children to use this product to avoid any damages to the fan or injury to the body due to inappropriate usage.