A Circus I.D. is a bracelet instilled with great power that can only be "activated" by its owner. They are used exclusively by the members of Circus.
It gives them the ability to fly and perform various special attacks.
There is a heavy price on stealing Circus I.D.s. Usually when someone other than the owner wears it, the I.D. will self-destruct.
All old versions of Circus I.D.s are supposed to be terminated- destroyed or invalid.