On May 24th, 2017, a few days before the opening day of the Pandora: The World of Avatar land actually opened, these bands became available for sale. It’s a Limited Edition 2000, comes in a special box, and makes special effects at the Pandora ACE touch points. The cost is $32.99 and the barcode SKU is 400020187673.
The sounds are of a viper wolf growl (which is the image on the band itself):
https://www.youtube.com/watch?v=dCf8lSGUWdg