I recently purchased this Powerball after reading the Reviews on this site. A lot of people commented on how well it works the muscles in your arms. Particularly the forearms.
I am a guitarist in a Thrash Metal band which for those of you unfamiliar with the genre it requires extremely Strong forarm muscles in the picking hand to play fast for long periods of time and it also requires powerful wrist and fingers in the left hand for the fast solos.
So i purchased one of these powerballs to out of cuiosity to see how it would work my muscles.
Its great it builds to an incredible intensity which challenges both my forearms and as it gets faster my fingers to hold onto it.
i think its a must have gadget for musicians Particularly Guitarists and Drummers because of the strength required in the Forearms.
You can also increase the force on your fingers by holding it just between your fingers and not on your palm
Iv Definately felt an improvement in my stamina and Dexterity in the short time i have had this product