- "Whoa. Is that an interdimensional extrapolator?"
"If that's nerd talk for 'breach device', then yes; and I need you to fix it."
- —David Chin and Laurel Lance[src]
An interdimensional extrapolator is a device created by Cisco Ramon that allows the user to open breaches between different universes, or to allow instant travel between different locations within the same universe. They can also be used to travel through time.
Jay Garrick has one of these gadgets, presumably either given to him by Cisco or made by Jay himself, which the former wears in a wristwatch-like fashion.
Josh also has one of these devices.
Connecting Earth-1 and Earth-38
Fighting off an alien invasion on Earth-1
After Kara Danvers helped Barry Allen and his friends on Earth-1 fight off an alien invasion on his Earth, wishing to give Kara the ability to travel between Earths herself, Cisco Ramon created an interdimensional extrapolator and gave it to Kara as a gift, explaining that it had communication functionality between their universes. Kara later used it, opening a small breach from Earth-1 to Earth-38, traveling between them.
Attack of the Music Meister
Sometime later, Winn Schott examined the device, being impressed by it. When the D.E.O. brought in a new prisoner, he hypnotized Kara, broke out of his handcuffs and took the interdimensional extrapolator; using it to open a breach to Earth-1. He then threw the instrument back to Winn and proceeded to jump through the portal.
A short time later, J'onn J'onzz and Mon-El presumably made use of Kara's interdimensional extrapolator when they brought her to Earth-1 to get help from Team Flash as well as pursue Music Meister after he "whammied" Kara.
Barry and Iris's wedding
Kara and Alex used it to transport themselves to Earth-1 for Barry Allen and Iris West's wedding. After their trip, during which they helped to prevent a Nazi invasion from an alternate universe, they used it to return to Earth-38.
Jesse and Wally break up
It's possible that Harrison Wells of Earth-2 (Harry) possesses one of these devices, since, when his daughter, Jesse, was supposed to meet with Wally West on Earth-1 for a date (with Jesse being capable of passing between dimensions by way of the Speed Force), he instead came through a breach alone (presumably using some type of tech; such as an interdimensional extrapolator, to breach to Earth-1). He then delivered a break-up cube to Wally, per Jesse's request. Several months later, after helping Team Flash defeat the Thinker, Harry returned to Earth-2; presumably utilizing an interdimensional extrapolator to do so.
Connecting Earth-1 and Earth-X
Team Flash later enlisted Leo Snart's help to safely transport Neil Borman/Fallout into A.R.G.U.S. protective custody on Earth-1. Afterwards, Cisco gave Leo an interdimensional extrapolator of his own; suggesting that Leo and Ray, who were getting married, could use it to travel to Earth-1 for a honeymoon. Leo then used it to return to Earth-X.
Stopping the Enlightenment
While attempting to figure out how to stop Clifford DeVoe and keep him from carrying out the Enlightenment, after programming it with the necessary coordinates, Iris West-Allen and Harry Wells used an interdimensional extrapolator to breach themselves to England when looking for Clifford's estranged wife, Marlize DeVoe. Due to the fact that Marlize had abandoned her husband in disgust as a consequence of the latter's ruthless plans, Team Flash was confident she'd be willing and able to help them stop him. After reasoning with Marlize, Iris was able to convince her to work with Team Flash to stop Clifford.
Aftermath of the Enlightenment and the rise of Cicada
When Team Flash was trying to come up with ideas of how to stop Orlin Dwyer (a serial killer otherwise known as Cicada, who'd gained powers from an oddly-shaped piece of shrapnel from the S.T.A.R. Labs satellite, which DeVoe had knocked out of orbit into Central City after Team Flash foiled his plans for the Enlightenment), who targeted meta-humans, Nora suggested that they enlist the help of another version of Harrison Wells. When Team Flash contacted Harrison Wolfgang Wells, he politely stated that he was too busy to help them, but instead recommended they turn to Harrison Sherloque Wells, regarding him to be the best detective in the multiverse, and gave Team Flash his coordinates. Since Cisco's hands had gotten cut in a fight against Cicada, thus making it painful to try to use his powers to open a breach, Cisco used an interdimensional extrapolator to breach this new Wells to Earth-1. A short time later, in another confrontation with Cicada, who was hell-bent on killing Vibe, Cisco used Team Flash's interdimensional extrapolator to breach himself out of harm's way, as using his powers to open a breach was rendered impossible, not only due to his injured hands, but also because the presence of Cicada's dagger (which possessed capabilities to dampen the powers of dark matter-based meta-humans; like Cisco) completely negated his powers.
After Nora was "whammied" by Spencer Young's phone, a piece of meta-tech created in the Enlightenment (she read a news article written with the phone, which hypnotized her into trying to kill Barry), Iris used an interdimensional extrapolator to breach herself to their location and knock Nora out with a tranquilizing dart.
Later, Barry was abducted by Rag Doll (a meta-human who gained bodily contortion powers due to being crushed by a piece of the S.T.A.R. Labs satellite the night of the Enlightenment), who put power-dampening cuffs on the former and brought him to the top of a tall building, threatening to drop him. Since Cisco was still unable to open a breach due to his injuries, Iris contemplated using an interdimensional extrapolator to get herself to Barry's location to save him. However, this proved impossible since Sherloque had accidentally broken the team's only interdimensional extrapolator, and Cisco stated that it would take him at least an hour to fix the device. After this, Cisco presumably built more of them for the team to have on hand in case of emergencies.
Searching for Caitlin's dad
Caitlin, Barry and Cisco used an interdimensional extrapolator to breach themselves to the north pole when they were looking for Caitlin's father, Thomas Snow. After they found him in an abandoned Tannhauser Industries black-ops site, the four of them then used the instrument to return to S.T.A.R. Labs. A short time later, Cisco used the extrapolator to return to the black-ops site where they'd found Thomas in order to investigate, as he suspected that Thomas was hiding something.
Facing Cicada again
After Team Flash put a plan into motion to build an instrument to negate the powers of Orlin's dagger and get it away from him so they could try to get rid of the weapon in an effort to stop Dwyer (as the dagger's dampening properties put the group at a huge disadvantage when facing him), their device successfully canceled out the dagger's power-negating capabilities. After this, Cisco took the dagger and used an interdimesional extrapolator to breach the knife into outer space. They thought that this put enough distance between Cicada and the weapon (with which Orlin shared a psychic link; allowing him to draw it to himself when it wasn't in his possession) that he'd be unable to summon it back to him. However, they were wrong, and he recalled the dagger without any difficulty.
When Oliver and Barry each woke up one morning, and found that they'd swapped lives and realized that no one on Earth could tell who they really were (thanks to John Deegan altering the reality of Earth-1 with the Book of Destiny), they decided to go to Earth-38 to find out if Kara would recognize Barry as Barry, and Oliver as Oliver, using Team Flash's interdimesional extrapolator to travel to her universe. A short while after this, Cisco breached to Smallville (where Barry and Oliver had breached to meet with Kara) on Earth-38 (likely utilizing Team Flash's interdimensional extrapolator due to his injured hands) to tell Barry and Oliver that Team Flash believed that the two of them were telling the truth; also asking them to help deal with a robot terrorizing Central City back on Earth-1. Oliver, Barry and Cisco, accompanied by Clark Kent and Kara, then went to Earth-1 (presumably using an interdimensional extrapolator) to deal with the robot running amok in Central City. After the robot's threat was eliminated, Clark headed back to Earth-38 (likely using an extrapolator to return to his Earth), in case anything happened back on their world while Kara stayed behind on Earth-1 to help Barry and Oliver solve their dilemma. Later, after Barry, Kara and Oliver traveled to Arkham Asylum to investigate, Caitlin, Diggle and Cisco presumably utilized an interdimensional extrapolator when they breached themselves to Arkham to meet up with their friends to inform the latter trio that they'd been told by an alternate Jay Garrick that in order to fix things, they'd need to "get the Book"; though, at the time, none of them were certain what he'd meant by that.
A short time later, Querl Dox, Lois Lane and J'onn presumably made use of Kara's interdimensional extrapolator when they traveled to Earth-1 to aid Kara, Clark, Barry and Oliver in their battle against Deegan after the latter altered Earth-1's reality a second time.
Destruction of Earth-27
Bruce Wayne used an interdimensional extrapolator he'd built to breach himself to Earth-1 alongside his fellow Crime Syndicate of America members (Eddie Thawne, "Power Ring", "Ultraman" and "Superwoman") in order to flee Earth-27 when their world was destroyed by the Anti-Matter Man.
Protecting metas from Cicada
When rounding up meta-human former criminals to transport them into protective custody in an effort to keep them safe from Cicada, who'd begun targeting meta-humans with known criminal pasts, Barry (as The Flash) approached Shawna Baez, a meta-human also known as Peek-a-boo (whom Team Flash had fought before), at a bar, asking her to come with him for her own safety. When Cicada showed up, Barry left Shawna with an interdimensional extraplator, telling her to use it get out of there. Barry then engaged in a fight with Cicada, seeking vengeance after Orlin had severely injured Nora; Barry's daughter from the future. However, he ended up having to retreat and go with Peek-a-boo, as she was having trouble figuring out how to work the device.
Dealing with Icicle and Cicada II
After Sherloque Wells revealed to Team Flash that Nora had secretly been working with Eobard Thawne to stop Cicada, Barry ended up taking Nora back to the future, forbidding her from coming back in time again; stating that if she tried to time travel again, he'd feel it in the Speed Force. Iris disagreed with Barry on his making this decision without her. When Barry told the rest of Team Flash that he'd sent Nora back to her own time permanently, this caused some tension within the group. When Sherloque tried offering input on what Barry had done, Joe told Sherloque the latter had done enough. Sherloque disagreed; stating that they still had another Cicada (Cicada II) to catch, but Joe advised him not to say anything more. Sherloque then prepared to head home to his Earth; intending to use an interdimensional extrapolator to leave Earth-1. However, after an alarm went off in S.T.A.R. Labs (where he was), alerting him to an attack by Icicle at Tannhauser Industries, he instead used the device to breach himself to that location to help Joe save Barry, who was suffering from hypothermia induced by Icicle.
After Future-Grace/Cicada II stole Cisco's failed prototypes for the meta-human cure (which would prove toxic to meta-humans as they were the unfinished drug), planning to disperse it into the air to kill all meta-humans, though Team Flash and the CCPD were working to administer the cure to as many metas as possible for their safety, Harrison Sherloque Wells used an interdimensional extrapolator to send his girlfriend, Renee Adler to his Earth. He did this not only to ensure that she'd be safe, but also because she loved having her powers and didn't want to give them up.
When Team Flash went to the woods to the cabin where Grace had brought her comatose younger self, Joe West threw an interdimensional extrapoator at Future-Grace; forcing her through a breach formed by the device. This sent her into a force-field in S.T.A.R. Labs. A short time later, after the team had defeated Cicada II, Sherloque used an interdimensional extrapoator to return to his Earth; taking the device with him through the breach. However, given that Sherloque has been to at least 37 other Earths aside from Earth-1 (which may or may not include his home universe; Earth-221), it's possible that this was an extrapolator he'd owned previously, rather than being given the device by Team Flash.
Fighting the Ninth Circle
It's possible that Laurel Lance of Earth-2 has one of these devices, since, after officially leaving her criminal past behind her, she decided to go back to her home universe and operate there as a symbol of hope to the people of Earth-2 by formally taking up the mantle of the Black Canary. She later traveled back to Earth-1 to aid Team Arrow in their battle against the Ninth Circle, and subsequently returned to Earth-2 at some point afterwards.
When the Monitor sent Oliver to Earth-2 as part of their mission to prepare for the impending Crisis, John borrowed an interdimensional extrapolator from Cisco to travel to Earth-2 to help Oliver out. When Earth-2 ended up getting swallowed by a mysterious energy wave, John and Oliver, accompanied by Earth-2 Laurel, used the instrument to escape the destruction by fleeing to Earth-1.
A short time after this, at her first available opportunity, Laurel wished to go back to Earth-2; refusing to believe that her entire home world had simply vanished. Since the device had seemingly been damaged in their escape from Earth-2 (as she couldn't use it to open a breach to go back to her Earth), Laurel tracked down David Chin (an associate she knew from her time working with Cayden James) and had him fix it. After this, she attempted, once again, to return to her universe. However, as she learned that while the extrapolator was working just fine and could still take her to other Earths, no signal existed on Earth-2; forcing her to face the fact that her world was destroyed.
When Barry tried to run into the future, to December 11, 2019 to see what happened after he, according to the Monitor, died in the Crisis on December 10, 2019, Barry found his path through the Speed Force blocked by antimatter. This ended up giving him an injury that left him in a considerable amount of pain, prompting him to go to Earth-3 to get help from Jay Garrick; an expert on antimatter. While there, he met Jay's wife, Joan Williams (Barry's mother's Earth-3 counterpart), who was also a fellow scientist of Jay's. The two of them informed Barry that while it may not be possible for them to physically send him into the future, they may be able to project his mind into the future to see what was to come. This ended up leaving Barry worn out and in a good deal of greater agony, and they subsequently brought him back to Earth-1 to rest, as Barry insisted on seeing Iris. Later, they returned to Earth-3 using an interdimensional extrapolator in Jay's possession; potentially given to him by Cisco, or made by Jay himself.
Hunting Gypsy's killer
After Josh's daughter Cynthia (more commonly known under her code name; "Gypsy") was murdered, Josh, who'd begun losing his vibe powers (including the ability to open breaches) in his old age, used a special blade in his possession to create a tear in the space-time continuum in order to travel to Earth-1. He then informed Cisco of the former's daughter's murder; requesting Cisco's help in finding her killer. After the person who killed her (Cisco's Earth-19 doppelgänger) was apprehended, Josh used an interdimensional extrapolator of his own to breach away from Earth-1.
When Ramsey Rosso (self-nicknamed "Bloodwork") began an attack on Central City (transforming as many citizens as he could into Blood Brothers (having already infected Barry (turning Barry into a Blood Brother whom Cisco dubbed "Dark Flash"); making his reign of terror that much easier to carry out without the Flash standing in his way), Frost used an interdimensional extrapoator to breach herself into the streets to meet up with Captain Joe West. A short time after this, during Ramsey's attack, Iris, safe inside a force field Cisco had activated to protect S.T.A.R. Labs from Ramsey's minions, listened to what was happening outside via a police radio. When Barry sent her a message over the radio saying that he needed to see her; telling her to meet him where they began their life together; where she said "yes", Iris grabbed an interdimensional extrapoator and was ready to go meet him immediately. Cisco warned her that it was likely a trap laid by Dark Flash, but Iris firmly believed Barry was still alive in there. Against Cisco's objections, Iris insisted on going to see Barry; stating that their wedding vows meant being there for one another; "in sickness and in health". She then used the extrapoator to breach herself to their loft. When she got there, sure enough, Barry had been acting as Ramsey's puppet. Through Dark Flash, Bloodwork offered her the chance to join Barry as a Blood Brother. When Iris refused, Dark Flash threatened to kill her, but didn't. After stating that this wasn't over, Dark Flash sped off. Iris then used the device to return to S.T.A.R. Labs. A short time later, after Joe was injured battling the Blood Brothers, Frost and Allegra Garcia used an interdimensional extrapoator Frost had with her to get Joe to back to S.T.A.R. Labs for his safety. Meanwhile, Cisco used an interdimensional extrapoator to breach himself to Ramsey's location, zapping the latter with a photon emitter; a device Cisco had designed that released blasts of the same type of radiation used to treat cancer patients, which could theoretically strip Ramsey of his powers and also be used to cure the Blood Brothers. However, he hadn't had a proper chance to test it, and it didn't affect Bloodwork in the way he'd hoped.
Anti-Monitor Crisis and saving the multiverse
Finding Jonathan Kent
While facing the impending destruction of Earth-38 during the Anti-Monitor Crisis, Harbinger used her powers to bring Oliver Queen, his daughter Mia, Kate Kane, Barry Allen, Sara Lance and Ray Palmer to Earth-38 to try to stop the Anti-Monitor. The Monitor had wanted them to take their stand there due to the fact that Earth-38 was a key Earth, and that if they didn't stop the antimatter wave there, it'd continue destroying other universes. As Lois and Clark had sent their infant son, Jonathan, away from Argo City in a Kryptonian pod moments before the city was consumed by antimatter, when Lyla safely brought the pair of them back to the D.E.O., Brainy managed to track Jonathan's pod; concluding that it had been breached to Star City on Earth-16. While Clark, Kara, Oliver, Kate, Ray, Barry and Mia prepared to hold off the Anti-Monitor's army to buy time to evacuate Earth-38's inhabitants to Earth-1, as the antimatter wave was projected to reach Earth-1 last, Sara, Lois and Brainy used an interdimensional extrapolator to travel to Earth-16 to retrieve Jonathan, who had been found and taken to safety by that Earth's Oliver Queen. In doing this, they also had to travel through time, as Jonathan had wound up in the year 2046 on that Earth. After finding Jonathan, they used the device to bring him back to Earth-1.
Resurrecting Oliver Queen, saving doomed universes and finding the Paragons
After Oliver was killed during the battle against the Anti-Monitor's forces while trying to evacuate Earth-38, Barry Allen, Mia Smoak, Sara Lance and John Constantine used an interdimensional extapolator to travel to Earth-18, as they'd discovered that that universe had a usable Lazarus Pit. After finding the Pit, Barry and Constantine used the device to go back to Earth-1 and bring Oliver's body to Earth-18 so they could use the Pit to resurrect him. Afterwards, they presumably used the extrapolator to return to Earth-1.
Meanwhile, Lex Luthor stole the Book of Destiny and used an interdimesional extrapolator to jump between universes; using the Book to kill every version of Superman he could find in the multiverse. This is how Lois Lane and Clark Kent of Earth-38 and Iris West-Allen of Earth-1 were able to learn that Clark Kent of Earth-96 was the Kryptonian identified by the Tome of the Guardians as the Paragon of Truth (one of seven heroes that were vital to their hope to save the multiverse), whom they'd been sent to find; presumably having used an interdimensional extrapolator to travel to his universe (though they'd also traveled to Earth-75 and Earth-167 during their search, as they weren't certain what universe the Kryptonian Paragon called home; likely also utilizing an interdimensional extrapolator when they visited those Earths). After a brief tangle with Lex, they then presumably used their extrapolator to bring Earth-96 Clark (in addition to Lex Luthor) back with them to Earth-1. After this, Lex was locked in a force-field cell aboard the Waverider, and the Book of Destiny and the extapolator he'd used were taken from him.
During the search for the Paragons, Kate and Kara used an interdimensional extrapolator to go to Earth-99, as Mar Novu had told them that going there would lead them to the Paragon of Courage; also known as the Bat of the Future, whom they'd assumed to be that Earth's Bruce Wayne. However, upon returning to Earth-1 after journeying to Earth-99, they learned that the Paragon of Courage was in fact Kate herself.
While some of the heroes aimed to track down the remaining Paragons, J'onn J'onzz decided to work with Earth-96 Clark to bring as many people across the multiverse to Earth-1 for their safety, as Earth-1 was still the antimatter wave's last predicted destination. A short time later, Earth-96 Clark breached back to the Waverider, presumably through the use of an interdimensional extrapolator; frustrated after having failed to save the denizens of an unidentified dying universe. After speaking with Earth-38's Lois Lane aboard the ship, he breached away again; likely utilizing an extrapolator once more.
After resurrecting Oliver in the Lazarus Pit, and finding that the ritual Constantine would've used to go to purgatory to retrieve Oliver's soul couldn't work properly due to the Crisis, John needed another way to get to that plane in order to fully restore Oliver's soul to his body. At some point, Constantine had helped Lucifer Morningstar of Earth-666 out with something regarding Maze; leaving Lucifer in John's debt. With Mia Smoak and John Diggle in tow, Constantine ventured to Los Angeles on Earth-666 to collect on the favor Lucifer owed him; presumably using an interdimensional extrapolator to get to his Earth. Lucifer then gave them a card that could transport them to purgatory, though he stated that they'd have a limited time before they'd need to get back out.
A short time later, Cisco, Barry, Frost and Ralph presumably made use of an interdimensional extrapolator when they breached to the Waverider. Cisco then aided Ray in finishing the Paragon detector the latter was working on; allowing the heroes to identify the last three Paragons needed to save the multiverse.
- "Where's Barry?"
"He's in Lian Yu. I've been trying to radio him, but that place is a total dead zone."
"What about those clicky things you guys use?"
"The extrapolators don't work. Now that the multiverse is gone, the physics behind breaching has changed entirely."
- —Allegra Garcia and Cisco Ramon discuss how interdimensional extrapolators have become useless post-Crisis.[src]
After the multiverse was destroyed and reborn in the Crisis, interdimensional extrapolators became unusable; even to open breaches between different points on the same Earth, as the laws of physics regarding breaching have dramatically changed.
DC's Legends of Tomorrow