Specification working principle: The wind blows the paddle on the generator shaft to rotate, when a certain speed is reached, the motor starts to generate electricity, and the higher the speed, the greater the power generation voltage. It should be noted that it generally requires the wind force from a hair dryer to achieve higher voltage; natural wind may not be sufficient. Micro generator: 1. When the wind is strong, the motor voltage without LED lights or other loads can easily reach about 20V under no-load conditions. 2. The new motor with USB socket can be directly connected to the included USB light for use. Other low-power USB devices may not be reliably powered. Charging mobile phones or power banks is not supported due to the lack of a voltage regulator module. 3. When equipped with a regulated 5V module, the charging current is approximately 30mA under peak airflow from a household fan. For a smartphone with a 4000mAh battery, the theoretical charging time would be around 6 days. (Note: Market-available products in this category are generally not capable of effectively charging mobile phones or power banks. Even if some current is present, practical charging is not feasible.) Length: 18cm [Inner hole] 2mm (fastening) Material: ABS plastic Weight: About 4.8 grams [Installation] Positive and negative paddles can be fixed onto a motor shaft with a 2mm diameter. Usage: Lights up when exposed to airflow; can be installed on a bicycle to produce light while riding. Includes a USB light bulb with a 1-meter USB cable, 5 watts, which can be plugged into a power bank for emergency lighting as needed. Product includes: 1 x Micro Wind Generator, 1 x USB Light Bulb