The Rings' design is based on either the basic and round-edged wedding rings or solid brass round rings. In their base state, Rings are small to fit into the palm of the hand. When active however, they can grow to be a number of meters in diameter.
Powers and traits
With the user's mind, Rings can open portals to practically anywhere in the universe, from other countries to other planets on the far side of the universe. However, these portals are temporary, and once used, the Ring that made the portal will cease to exist.
Ten years ago, Longclaw gave Sonic the Hedgehog a Ring bag when escaping an echidna tribe. She also used a Ring to transport Sonic to Earth. For the next ten years, Sonic kept Longclaw's Ring bag in his cave near Green Hills.
Sonic the Hedgehog
When he was about to be discovered by the United States government, Sonic attempted to flee to the Mushroom Planet, but was tranquilized by Tom Wachowski. Spotting the Transamerica Building in San Francisco on Tom's shirt however, Sonic opened a Ring portal to the top of said building as he passed out and accidentally dropped his Ring bag into the portal, which closed before he could get through it.
Days later, Sonic, along with Tom and Maddie Wachowski, managed to recover his Rings in San Francisco. Soon after, Sonic used a Ring to sent Tom and Maddie to Green Hills after Dr. Robotnik attacked the trio. Afterward, Sonic would use his Rings to transport himself to other countries, though Robotnik managed to keep up with him and follow him through the Ring portals. Eventually, Sonic and Robotnik ended up in Green Hills with the use of a Ring. There, Tom would use a few Rings to assist Sonic and eventually banish Robotnik to the Mushroom Planet.
Later, Tails used a Ring to go to Earth, having tracked Sonic there.