A USB drive is a small computer storage device that connects directly to a USB port with a built-in connector. Drives store files on flash memory. Many different capacities exist. The most commonly used ones are 1 to 2 gigabytes, but capacities from 8 megabytes up to 12 gigabytes have been produced.

Some drives have a light that blinks to show if it is being used by the computer. Other features include a switch to protect files from being erased, password protection, and a fingerprint reader.

On one end of a drive is fitted a single male type-A USB connector. Inside the plastic casing is a small, highly cost-engineered, printed circuit board. Mounted on this board are some simple power circuitry and a small number of surface mounted integrated circuits (ICs). Typically, one of these ICs provides an interface to the USB port, another drives the onboard memory, and the other is the flash memory.

The essential components of a typical flash drive are: Male type-A USB connector, USB mass storage controller, A NAND flash memory chip and the Crystal Oscillator. A typical device also includes Jumpers and test pins, LEDs, Write-protect switch, Unpopulated space, USB connector cover or cap and perhaps the Transport aid like a keychain or lanyard.