|Featured in||The Stormlight Archive|
Spanreeds, like all conjoiner fabrials, are made by capturing a spren inside a ruby and splitting it in half. The two halves are then embedded in reed pens. The two pens can then mimic the movements of the other, exactly. The energy required for the second pen to move is provided by the holder of the first pen, which feels twice as heavy as an ordinary pen would.
The setting of the ruby can be rotated to switch between different "modes." One is to alert the possessor of the spanreed's twin that a conversation is desired. Another to alert the first that the message was received. The third and fourth notches sync the movements of the two pens, each notch makes one pen the transmitter and the other the receiver. Vorin men who do not write can communicate with a spanreed by turning the gem on and off to indicate that they are still alive.
By the sixth year of the War of Reckoning spanreeds have achieved widespread use, at least among the Vorin nations, from the Shattered Plains, to Kharbranth, and even to the isolated estates of House Davar.
Tashikk is beginning to become a spanreed hub, with several people and places having reeds connected to various businesses in Tashikk. The Tashikk operator is hired by the remote user to exchange messages, to research on your behalf, and to make other enquiries.
Spanreeds cannot be used effectively whilst moving when its pair is stable. Since the function of fabrials is dependent on the user's frame of reference, a spanreed in motion would be incapable of relaying a clear message to its stationary pair. If both spanreeds are on the same ship, for example, then the spanreed would function properly because both users have the same frame of reference. This is also why spanreeds are unaffected by the planet's motion and curvature.