Pendants are used in conjunction with tuning crystals to access the ESP network. All that is needed to access the network is a crystal pendant, but many people will augment these with the colored tuning crystals. Many of the organizations and towns in the Lost Lands have their own color of tuning crystal and use it for communication of official business. Tuning crystals have a short life span, and so often people will only tune to them to conduct the conversation, and then go back to gray.
Gray is the default color of the network and used for general communication.
They can be purchased in most post offices, and new characters have a temporary one upon beginning their adventure.