Long press the button to enter the highest setting (Speed 4). 2. The highest setting will only work when the output current up to 2A. With low/medium/high/super wind speed level, this variable speed design provides you more choices in different temperature environments. Super Quiet Although the fan is very strong, even in high speed the noise is less than 50dB. It is a quiet and good friend when working and sleeping. Ideal for your desk, office bedroom use. Powered by USB No battery included, powered by a 4.9ft USB cable, compatible with computers, laptops, power banks, wall chargers and any other USB-enabled power supply. USB fan is very energy-saving and environmentally friendly. Adjustable & Easy to Clean Fan head is able to tilt from 0 to 90 degree to direct the airflow to where you want. Removable front cover is easy to remove for cleaning the fan blade. Small but Powerful 5.5 Inch blade and 6.5 inch frame. Compared with the old version USB metal fan, this fan pushes packs a huge punch and cools you down quickly.Don't look it down because of its small appearance. You will surprise by how super strong the airflow is.