Interdimensional extrapolator

The interdimensional extrapolator is a device that Cisco Ramon created; that allows Kara Danvers to travel from Earth Thirty-Eight to Earth One any time she wishes, as well as communicating with him.

Team Flash later enlisted Leo Snart's help to safely transport Neil Boreman into A.R.G.U.S. protective custody on Earth One. Afterwards, Cisco gave Leo an interdimentional extrapolator of his own to return to Earth-X.

History
Wishing to give Kara Danvers the ability to travel between Earths herself, Cisco Ramon created an interdimensional extrapolator. He gave it to her as a gift, also explaining that it had communication functionality. She later used it, opening a small breach from Earth One to Earth Thirty-Eight, traveling between them.

Sometime after, 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 transport himself to Earth One.

Kara and Alex used it to transport themselves to Earth One for Barry Allen and Iris West's wedding. After their trip, and helping prevent an invasion, they used it to return to Earth Thirty-Eight.