Great, but be careful! 5

Assiduously playing bass lately, I wanted to offer me this gadget when I realized that if I let go several days without touching a handle, things were much more difficult when I was recovering myself .
The force (flexible) of each piston allows good to work each finger as needed.
But, be careful!
As was very well explained Jeff Berlin (a guy who knows what he's talking about), if you use this stuff every day, you are well your muscles hand, but in return you will lose dexterity on the handle of your bass guitar.
In addition to the ability to press the strings, making the speed of the game is the joint - "flexibility" if you prefer. And muscles do not facilitate this flexibility.
In short, this exercise tool is great (especially for such a price) if you only use it occasionally, not lose what you already have. But use it then by alternating your fingers (not all the fingers together, what) that the independence and responsiveness of your pretty phalanges do not suffer too much.