THe dyna flex found on this web site http://www.bindependent.com/hompg/b...dexercise.htm#Hand Exercisers#Hand Exercisers This device makes it feel like you've practiced 2 hours before you pick up your bass. You still have to practice but this thing wakes up your arms fingers and mind. It's a gyroscopic ball that gains mass as you spin it. It mimics finger picking and fretting with the left hand. It is a short cut but you still have to practice. I highy recommend it. I was able to increase my speed to 16th notes at 160 beats per minute with in a month of using this thing. It strengthens your fingers arms and mind in a short time. Don't get those finger exersizers from the music shop they don't work this thing does. It's my bible.