I watched the crossover between Supergirl and The Flash and as probably all of you also did, noticed a device we hadn't really seen before on Barry's chest.
I can only assume it has something to do with the blueprints he got from Wells but we haven't seen that thing before.
Was The Flash in Supergirl a future version of The Flash or is it just because both series don't run simultaneously?
And the main question is what that device does for him? Anyone who knows this through any other sources? Comics, etc..