From DivNull RPG
These small, paired jars, usually no bigger than a large wine jug, are perfect for moving small items vast distances. Once an item has been placed in one of the pair the user may spend 10 motes to instantly transport it’s contents into the other jar, no matter how far away. The jars are limited in what they can transport, however. No living thing more complicated than live herbs and grasses may be sent, nor may any enchanted object, as the Essence interferes with the transmission of the object. If one jar ever leaves Creation, whether it enters the Underworld, Yu-Shan, the Wyld or Malfeas, its companion jar will lie dormant until its return.
Cathak Cacek Omnus possessed one of these, with which he communicated with someone named “A”. The circle has it now, sending false message to A.
The circle was given another one by Hammer in the Woods, for exchanging intelligence.
Source: Odin, from the Exalted Wiki