Gringotts Wizarding Bank mail system

The Gringotts Wizarding Bank mail system was a system of pipes that delivered mail throughout the bank. The mail was transferred in the form of paper airplanes, similar to the interdepartmental memos used at the British Ministry of Magic. The pipes also served a secondary purpose; the mail was ejected from them at such a great velocity that it could harm humans upon contact, and thus the pipes served as a part of the bank's security system.

Appearances

 * Harry Potter and the Deathly Hallows: Part 2 (video game)