A silver ring worked in braided spirals. A ter'angreal. Channeling Spirit into it leads one into sleep, then into Tel'aran'rhiod.

References (Possible Spoilers)#

  1. In The Dragon Reborn
    1. TDR,Ch13 - The silver ring and several other ter'angreal are stolen from the White Tower by Liandrin and her Black Ajah cronies.
    2. TDR,Ch21 - Verin gives a list of the stolen ter'angreal to Egwene.
  2. In Knife of Dreams
    1. KoD,Ch15 - The silver ring is recovered from Ispan.
    2. KoD,Ch15 - Elayne keeps the silver ring so she can enter Tel'aran'rhiod if she can channel well enough.