The ECCN number for an ordinary external hard drive is 3AR99. However, other hard drives, particularly those that have been encrypted, have an ECCN number of 5A992.
An ECCN number is an alphanumeric code used to identify whether an item requires licensing permits in its exportation and re-exportation to other countries. This code is used on the Commerce Control List, and is given to items based on their nature and specifications to control their exportation.
The first character of the ECCN code identifies its Commerce Control category. There are 10 categories, with the first being nuclear materials and the last propulsion systems. Items that don’t fall in these 10 categories are all given an ECCN number of EAR99, and most of them don’t require a licensing permit to export. Other items, such as encrypted hard drives, fall in one of the categories. The "5" in an encrypted drive's ECCN code indicates that it's in the telecommunications and information security category. The next character is an identifier of the product group, and they are lettered from A to E. The "A" in ecrypted drives' ECCN shows it’s in the systems, equipment and components product group. The other digits identify the purposes for the control of the item.