Dominator technology

When the Dominators arrived on Earth, they used a mind control device to take control of Kara, Sara, Mick, Ray, Diggle, Thea, Martin and Jefferson though the heroes are are later freed from it's control. Later the Dominators attempted to eliminate all metahumans on Earth using a meta bomb before they are stopped by the Legends, Flash, Green Arrow, Spartan and Supergirl of Earth Thirty Eight. After the Dominators fled, A.R.G.U.S. kept a piece of their technology for safekeeping but Barry uses it to try to trap Savitar in the Speed Force but ultimately fails due to Savitar wielding the Philosopher Stone.