Stamp

A way of sending messages that's both instant and completely private? When you have magic anything is possible. Send that hand written letter to your aunt or receive a book from your co-conspirators, who will know?

The stamp is a fairly common sight, but this stamp is slightly different. Unique to each person and imbued with magic enough to carry the letter or parcel through the Tunnels to where ever it needs to go, it truly is the perfect postal system.

Utility

This technology is used for quick and private communication between individuals from anywhere in the world.

It has been used for many purposes from the passing on of family news to the plotting of international schemes, who says that stuff can't do two things?

Manufacturing

Each stamp is unique, created by the user and can only be used by them. It is difficult to learn how to do but as the stamp only needs to be made once to be used for the rest of a person's life which makes it well worth the effort to learn.

Social Impact

This technology has allowed for private communication across the world which has led to the spread of forbidden ideas and started several revolutions in both the magical and non-magical worlds.

Inventor(s)

The name of the inventor has been lost to time, but maybe that is how they would always have wanted it. They created a technology too enhance anonymity after all.

Access & Availability

The Government at Hearthwell House does not really want people using this means of communication so they have created 'easier' ways however they cannot really stop the use of this means of communication given it's secretive nature.