USB flash drives are generally classified under 852351 as solid-state non-volatile semiconductor storage devices. They are distinguished from ADP storage units (which are classified with computers) by the fact that they are not designed to be installed inside an ADP machine as a principal storage component. Portable, plug-in flash drives belong under 8523; internal SSDs designed for ADP systems may be classified differently. Verify against the specific article's design and applicable CBP guidance.

The distinction is the storage and processing technology embedded in the card. A magnetic stripe card (852321) stores data on a magnetic stripe and has no processing capability. A smart card (852352) contains an integrated circuit chip that can store, process, and communicate data — including contact and contactless (RFID/NFC) variants. Cards combining both a stripe and a chip are classified based on the principal function, typically as smart cards.