Power Rings

From the Sonic News Network, the Sonic Wiki

Generated from the Power Rock, these power rings that Uncle Chuck invented can only be used by Sonic. They give Sonic a temporary extra boost in speed and power. Though Sonic is the only one who can use them, Robotnik did once use a power ring to power a device he created to track anything moving with super speed. Power rings appear once every 24 hours and the pond from where they come is guarded constantly. It is golden yellow and found at Pond in Knothole.