A USB device, or Universal Serial Bus, is a removable data storage device that functions using flash memory.  They can be used in almost any computer and are able to store various file formats, including documents, audio, video, and more.  USB devices are also used for “plug-and-play” hardware, such as keyboards, mice, printers/scanners, speakers, headsets, and game controllers.  Some USB devices are used wirelessly; for example, a wireless mouse can be used on a laptop via a corresponding USB device that communicates with the mouse using infrared radiation or a bluetooth signal.

Compared to previous portable data storage devices, such as floppy disks, cassette tapes, and writable CDs, the USB device has several advantages.  First, its smaller size and universal format makes it very portable and transferable, and the flash memory can hold significantly larger amounts of data with rewrite capabilities (unlike compact disks).  However, it does have disadvantages because of its size and portability; malicious files and programs can be easily and often unknowingly transferred between computers on USB drives.  The universality of the USB device may also pose a security risk for companies that store sensitive information on their computers.  Some companies remedy this situation by disabling the USB drivers, the computer’s programming that allows it to recognize and run the USB device, or by manually blocking the USB hubs, destroying them, or filling them with resin or epoxy.

USB devices can also be used to provide power charging to certain objects.  For example, the Amazon Kindle comes equipped with a USB cable to transfer files from a computer onto the Kindle, as well as an adapter that fits standard electrical outlets.  The Kindle can be charged from either the USB plugged into a computer or into the electrical adapter.  Many cell phones, smart phones, and other handheld electronic devices can be charged using USB-to-outlet adapters, and some USB adapters have been designed to direct power from a car’s cigarette lighter.

USB drives are sometimes sold in promotional or novelty shapes/designs and are also known as pen drives, thumb drives, and jump drives.  The universal symbol for USB devices is known as the “trident logo” and is used to indicate USB hubs on hardware and the USB end of cables.