The Millennium Ring
Dahye's is made of one red band with all kinds of sparkle.
Symbol for unbreakable love.
Hyeonsoo's Millennium Ring has an Ouroboros.
Ouroboros is a symbol used in ancient cultures around the world. It consists of a snake biting its own tail, forming a circle, and like other circular motifs, it can symbolize unity or the cyclical nature of many aspects of life. The "tail-devourer" is the symbolization of concepts such as completion, perfection and totality, the endless circle of existence, etc. By swallowing its own tail it expresses the essence of Gnostic esotericism. It is both an amulet against suffering and a representation of the cosmos, "the circle of eternal becoming," often meant with the words "One is the All."
Both circles are red as this color belongs to number 1
Have a nice day :)