Widely Used -- The 4inch inline duct fan is widely used in homes, offices, warehouses, restaurants, bars, shops, shopping malls, grow tents, greenhouses and other where a lot of air is needed. Over-heat - The motor comes with low operating temperature and low heat generation, the built-in temperature device, the contact point is disconnected when the motor overheats, which acts as a power failure . double is . -- It is designed with high quality sleeve motor, quiet and energy efficient, with rotational speed 2800 r/min, 140 CFM . DIY Your HVAC System - You can supply air with one or more fans to DIY air circulation depending on the size of your space. It is to move air through carbon filters, long stretches of ducting or grow light reflectors. Exchange stale air with air to keep temperature or humidity under control and cool your reflector with our blower! Safe and environmental friendly. Colour: white Material: metal Voltage: 220V 50Hz Input power: 25W Speed: 2800R / Min Air volume: 140m3/H Running noise: 30-35db size: Diameter: 93 mm Height: 78 mm Package Contents: 1 x duct fan Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.