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 test without appropriate protective measures. After exceeding 100,000rpm, heat buildup may occur. Avoid prolonged operation at maximum speed. You can reduce the voltage to prevent reaching peak speed, or use a controller to slightly lower the speed. Warm Tips: 1. Do not stand directly in front of or behind the fan. The jet fan may suck in debris and eject high-speed fragments. Some videos online demonstrate dangerous stunts to showcase jet fan power. Do not imitate these actions. 2. Aluminum alloy housing is heavy. While it provides strong thrust, it is not suitable for model aircraft. Ideal for DIY enthusiasts and other applications. Color: Silver Material: Aluminum alloy Package Contents: 1 x 160000 rpm DC brushless motor Only the above package content is included; other items are not part of the sale. Note: Lighting reflections and differences in display screens may cause slight variations between the color shown in the image and the actual item. Measurement error allowance is +/- 1-3 cm.