''This article should be merged with keydrive

A Thumbdrive is a USB "mass storage" device that typically is about the size of your thumb. They contain flash memory and take their power from the USB connection of the PC they are connected to.

The Thumbdrive is quickly replacing the floppy disk as a portable data device. Sizes are measured in Megabytes and typically are 32 Mbytes or larger.

Some Thumbdrives have a physical "write protect" switch so they may be plugged with impunity into a system that might harbor a virus or worm (when set to write protected).