Velocity 9 is, in the comics, a serum that can bestow (or in Jay’s case restore) super-speed powers. It’s just one of a number of artificial ways to gain such powers, one of which is the Speed ...

The Flash: How Barry discovered Zoom's identity. ... (Grant Gustin) faced off with a female speedster, Trajectory, who was addicted to the Velocity-9, so much so that she overdosed, ...

Jay takes the Velocity-9 and speeds off to the rescue, evacuating everyone out of the building, but collapsing when he comes back to the lab. He assures Caitlin that he is just tired, and goes off ...