Buy 5V DC fans from a general electronic supplier, adapt a USB plug on it. Some fans will be rated 12V but accept lower voltage (and turn slower). This will be on their data sheets.
Anything sold as a USB fan will be a gadget.
Buy 5V DC fans from a general electronic supplier, adapt a USB plug on it. Some fans will be rated 12V but accept lower voltage (and turn slower). This will be on their data sheets.
Anything sold as a USB fan will be a gadget.