Sling Ring

"Mastery of the Sling Rings is essential to the Mystic Arts. It allows us to travel throughout the Multiverse. All you have to do is focus. Visualize. See the destination in your mind. Look beyond the world in front of you."

- Karl Mordo

A Sling Ring is a mystical object which enables the wearer to open a fiery portal to another location.

Sling Rings are small two-finger rings imbued with the power to sustain dimensional portals between any two points on the planet, and also, although it requires much effort, throughout the Multiverse as well. They are used by the Masters of the Mystic Arts, and their apprentices, to facilitate long distance travel where a temporary portal is desired. Sling Rings are typically worn on the left hand when conjuring a portal, and this is achieved by the wearer tracing their right hand in a circular pattern while focusing on a destination beyond the space directly front of them. Most of the time they are simply carried until needed, typically somewhere on a user's belt.

Retrieving the Dark Scepter
To be added

Theft of the Book of Cagliostro
After the Ancient One killed several of the Zealots in the Mirror Dimension, Kaecilius used his Sling Ring to open a portal to flee to a park-like area. The portal closed before the Ancient One could follow. She used her own Sling Ring to travel back to the real world.

Strange's Training
At first, Doctor Strange found it difficult to use the mystic device, able to only generate orange sparks where his peers were able to summon full portals. As "encouragement" the Ancient One used her Sling Ring to transport Strange to Mount Everest and left him there with his Sling Ring. Strange managed to use his Sling Ring get back to the Kamar-Taj before he froze to death.

Battle at the New York Sanctum
Kaecilius and the Zealots used Sling Rings to travel to the New York Sanctum. When Strange managed to trap Kaecilius in the Crimson Bands of Cyttorak, the Zealot noticed that the amateur sorcerer had lost his Sling Ring, distracting Strange long enough for Lucian stab Strange.

Doctor Strange used Kaecilius' Sling Ring to open a portal to Metro-General Hospital in search of Christine Palmer to cure his wound from Lucian's sword. In his haste to seek help, he accidently left the portal open, allowing the Zealots' Astral Form to follow.

After being saved by Palmer and duelling Lucain, Strange led Palmer to the janitor's closet where he opened the portal, after stepping through back to the New York Sanctum, Strange used the Sling Ring to close the portal.

Battle at the Mirror Dimension
During the Battle of the Mirror Dimension, Doctor Strange tried desperately to use his Sling Ring to escape the dimension, only for the Zealots to warp the world around the portal, causing Strange to loose his focus and destroy the portal.

The Ancient One used her Sling Ring to enter the alternate reality to duel Kaecilius. Kaecilius let his Zealots attack her before stabbing her and using his own recovered Sling Ring to push her hundreds of stories to the mortal ground below.

The sorcerers used their Sling Rings to escape the Mirror Dimension after the battle.

Battle at the Hong Kong Sanctum
Kaecilius and the remaining Zealots used their Sling Rings to travel to the final Sanctum Sanctorum and destroyed it. Doctor Strange and Karl Mordo used their own Sling Rings to travel to the same area. After the battle, Mordo left the Masters of the Mystic Arts and took his Sling Ring with him. Wong and Strange presumably used their Sling Ring to return to Kamar-Taj.

Trivia

 * The portals created by the Masters of the Mystic Arts through the Sling Rings shares numerous similarities with the Inter-Dimensional Gate, as they both channel extra-dimensional energy from other dimensions to open a door to a specific place in the Multiverse.
 * Ghost Rider was also able to open a very similar looking portal to another dimension using not a sling-ring but his chain.
 * Doctor Strange wears his Sling Ring under his gloves, so it can't be taken from him easily.

Behind the Scenes

 * While most of the magic and artifacts in Doctor Strange are taken straight from the comics, the Sling Ring is an original item created specifically for the movie. Director Scott Derrickson explained, "The gateways, the forming of the gateways that are used for that, that's straight out of the comics. I just needed an object for them to carry it on."