From Supernatural Wiki:
Famine’s ring is a ring that helps the Black Horseman, Famine, channel and focus his powers. Without it, in the physical world, he is left, as the demon Brady puts it, a “withered husk”. Sam and Dean obtained Famine’s ring after Sam exorcised demons out of Famine’s body. includes a small rare earth magnet you can easily install which brings all the horsemen rings together except war .contact me for a suitable magnetic ring for cosplay.