Waiting for my bulk 3 to close and start its delivery. Daijoubu, shall us the bulk 3 expect some good news when you return?

To be more precise, it can build muscle strength, not mass. Meaning you will get stronger arm, but not size. Unless you are really thin, then will see some muscle growth. I believe, the powerball exercise is meant for training muscle contraction and muscle coordination (when we switch between different muscles to flex the ball and sustain the vibration). To build mass, you need to do slow and heavy lifting.