Specification: Working principle: Wind blows the paddle on the generator shaft, causing rotation. Once a certain speed is reached, the motor begins generating electricity. Higher wind speed results in higher voltage output. Note that it typically requires airflow from a hair dryer or similar source to achieve higher voltage; natural wind may not be sufficient. Micro Generator: 1. In strong wind conditions, with no load such as LED lights connected, the open-circuit voltage can reach up to approximately 20V. 2. The unit features a new motor with a built-in USB socket, allowing direct connection of the included USB light. Other low-power USB devices may not be reliably powered. Charging smartphones or power banks is not supported due to the absence of a voltage regulation module. 3. When equipped with a regulated 5V module, the charging current is approximately 30mA under maximum airflow from a household fan. For a smartphone with a 4000mAh battery, the theoretical charging time would be around 6 days. (Note: No product in this category is capable of practically charging mobile phones or power banks under normal conditions. Any apparent charging capability would not be meaningful in real-world use.) Length: 18cm [Inner hole] 2mm (for shaft fixation) Material: ABS plastic Weight: Approximately 4.8 grams [Installation] Equipped with positive and negative paddles, designed to fit securely on a motor shaft with a 2mm diameter. Usage: Generates power when exposed to airflow, such as when mounted on a bicycle to produce light during riding. Includes a USB light with a 1-meter cable and 5-watt output, compatible with power banks for emergency lighting. Product includes: 1 x Micro Wind Generator 1 x USB Light Bulb