Within Doctor Strange's Greenwich Village Sanctum Sanctorum, in a room sometimes referred to as the Chamber of Shadows, sits a 3-legged case which is the resting place of the mystical crystal known as the Orb of Agamotto. When Doctor Strange summons the Orb, it rises from its case and activates.
The Orb is a powerful scrying device that can automatically detect the use of powerful magic around the world, pinpoint the user, and reveal his or her presence to its master. It also detects any great evil threat to the world and shows its location to its master (Judge's discretion).
The Orb will also automatically allow its user to peer into other dimensions and other worlds that he has previously visited or has knowledge of. Like the Eye of Agamotto, the Orb has been able to provide a dimensional aperture through which Strange has been able to pass into other dimensions. No FEAT rolls are required for any of these functions unless the character using the Orb has never used it for that specific function. To use the Orb for the first time requires a successful Psyche FEAT roll. If the roll is failed, the user must wait 24 hours to attempt that function again.
Especially powerful mystical forces have, in the past, been able to cloud the Orb and prevent Doctor Strange from uncovering their exact location (this requires a Red Psyche FEAT roll by the party involved in clouding all scrying). While there is obviously some manner of connection between the Orb and the Eye, both of their origins are clouded in mystery.
The Orb of Agamotto contains its own dimension.