Which is the most reliable free antivirus for USB flash drives?

[priyamtheone]

Which is the most reliable free antivirus for USB flash drives that resides and runs from the device itself and doesn't need to be installed on the computer?

[codegazer]

You could have a look at ESET. It requires a minimum of installation and is very effective, but I don't know if it can work from a USB drive.

I use it online from time to time to make a second sweep for any malware that my installed antivirus might have missed.