It's the combination of exercises that does the trick
It’s the combination of exercises that helps smooth out the area between the brows. First you do the slide or "Pull" while you frown and then you work this area in the OPPOSITE direction with the "Push". Then there are 2 more steps to complete the process. This is how it works:
How does it work?
There's a little group of muscle (Procerus) between and just above the bridge of the nose and between the brows that needs to be worked. The only way to work this muscle is through the “Pull/Push” exercise. By working this part of the face in this way, this area (sometimes this area is called, “the elevens”) will eventually LAY FLAT. If you don't work this area in both directions, you may end up with little lumps on either side of the eleven lines as they smooth out. You must perform both the "Pull" and "Push" part of the exercise to prevent these bumps. THEN, you perform the "Worry Line Smoother" as the third step of this combination of exercises. The "Bridge Smoother" is the last step of the process and over time the area between the brows will be less lined or even free of lines and be flat and smooth, giving your face a younger and more relaxed look. You can read more here