How They Work
The rings can shrink to the size of wrist-bands, and grow to a size of a door. To go where you want to go, you need to touch brim of the ring and think of the spefic place you want to go.
Super Warp Rings
When Warp Rings receive a super charge, like when Scourge charged his with the Master Emerald, they can allow Travel to other dimensions. According to Sliver, Super Warp Rings can also be used for time travel. Super Warp Rings have an aura of energy around them.
It is suggested that the charge for Super Warp Rings fade over time, as Scourge used one to bring him and Fionia from Mobius to his world of Moebius but need to steal Dr. Kintobar's Globe Post in order to travel back to Mobius. Also, Sliver used the Super Warp Ring when he left Moebius, in order to fix his future and see who was the traitor of the Freedom Fighters, but in Sonic Universe 8, he leaves the future time-line of Mobius with a Chaos Emerald while saying "Chronos Control."