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. You can reduce the voltage or use a controller to slightly lower the speed to prevent reaching the maximum speed. Warm Tips: 1. Do not stand directly in front of or behind the fan. The jet fan may ingest debris and eject high-speed fragments. Some videos online demonstrate dangerous stunts to show the power of jet fans. Do not attempt these. 2. The aluminum alloy housing is heavy. Although it provides strong thrust, it is not suitable for use on model aircraft. It is suitable 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 effects and different display settings may cause slight color differences between the image and the actual item. Measurement error is allowed within +/- 1-3 cm.