A ring of dragons was a magic ring that, as the name suggested, bestowed dragon-related powers. They were highly coveted, and used by the Cult of the Dragon, particularly within their leadership. By 1372 DR, 70 or so rings had been crafted.
The wearer could communicate verbally (such as by tongues) or telepathically (in the manner of Rary's telepathic bond) with any dragon he or she could see. They could also cast a silent image once a day of any dragon he or she had seen with their own eyes.
They could also call to any dracolich or evil dragon by name, although this did not guarantee that the creature would respond or arrive, or be helpful. The dragon or dracolich knew the wearer's location and could use it to locate them. The call continued until the user ended it, removed the ring, or died.