BTOOP 4 Inch Mini USB Desk Fan - Small - Black The desk fans made of anti-rust and metal frame. And every fan will test when send it out. This small fan is with four aluminum blades and a powerful motor to make the wind powerful enough, the airflow up to 3.8m/s This usb desk fan is with three anti-vibration pads to help the fan reduce noise and make the fan more sturdy.So it is quiet enough to use at home and office. This personal fan saves your desk space, little but strong. Adjust the direction of the wind with 360 up and down adjustment. This USB portable fan is powered by a 3.93ft usb cable,compatible with desktop,computers,laptops,power bank and other devices with USB output. But it can not plug to wall outlet.