Notes: We are one of the earliest manufacturers to modify metal jet fans. Please note that this 40mm jet fan offers excellent cost-performance value. Jet fans operate at extremely high speeds and with high power. Do not operate without proper protective measures. After exceeding 100,000rpm, heat buildup may occur. Avoid continuous operation at maximum speed for extended periods. Reduce voltage or use a controller to lower the speed as needed. Warm Tips: 1. Do not stand directly in front of or behind the fan. The jet fan may draw in debris and eject high-speed fragments. Some online videos demonstrate dangerous stunts to show fan powerdo not imitate. 2. The aluminum alloy housing is heavy. While it provides strong thrust, it is not suitable for use on model aircraft. Ideal for DIY enthusiasts and other applications. Color: Silver Material: Aluminum alloy Package Contents: 1 x 160000 rpm DC brushless motor Package includes only the items listed above; other products are not included. Note: Lighting and display differences may cause slight color variations between the image and the actual item. Measurement tolerance: +/- 1-3 cm.