The walker bracelet and ring is one set of jewelry made out of a silver like material. These items allow persons from another world come to ours by merging and taking over the control of the body who wears the jewels. The braclet and ring is not unique, hundreds of them are in the magic shop not to mention in the pararell world which let you visit the other world the same way.
When you wear the bracelet you practically offer yourself as a vessel for someone with another bracelet. During this time people can telephatically talk to you about a deal, how long would they possess your body, what they want to do with it and what do they offer for your services. If the deal is done between the 2 person the one who will get possessed will put on the ring. The ring is like an assurance, it will fall off by itself when the decided time limit is over or anything happens that was not part of their deal.
With the ring on the merging begins making the host resemble the passenger.
The jewels are from the other world where magic is real and mostly populated by anthro animals and mythical creatures intented to let them walk in our world where the dominant species are humans without causing panic.