Specification working principle: The wind blows the paddle on the generator shaft to rotate, and when a certain speed is reached, the motor starts to generate electricity. The higher the rotational speed, the greater the generated voltage. Note that it typically requires airflow from a device such as a hair dryer to achieve higher voltage output, as natural wind may not provide sufficient force. Micro generator: 1. When wind speed is sufficient, the motor generates voltage without connecting LED lights or other loads. The no-load voltage can reach up to approximately 20V. 2. The motor features a built-in USB socket, allowing direct connection to the included USB light. Operation with other low-power USB devices is not guaranteed. Charging smartphones or power banks is not supported, as the unit does not include a voltage regulation module. 3. When used with an external 5V voltage regulator module, the charging current is approximately 30mA under maximum airflow from a household fan. Given these conditions, charging a 4000mAh smartphone battery from zero would require approximately 6 days. (Note: No small wind generators available on the market are capable of efficiently charging mobile phones or power banks. Even if minimal current is detected, practical charging is not feasible.) 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 be securely mounted on a motor shaft with a 2mm diameter. Usage: Lights up when exposed to airflow, or can be installed on a bicycle to power lighting during riding. Includes a USB light with a 1-meter cable and 5-watt output, compatible with power banks for emergency lighting use. Product includes: 1 x Micro Wind Generator 1 x USB Light Bulb