I've been using grippers to squeeze for hand strength for years. The ones you get in the sporting goods stores are a joke--it would take several hundred reps to make your forearm tired.
I bought the 100 pound version from Irong Mind about 6 months ago. For the first 3 months it was a challenging workout. I did 6 sets of 10 reps with the grippers in two positions: The conventional position with the coil at the thumb end of your hand; and the less conventional position with the coil at the pinky end of the hand.
In the beginning the sets were difficult/impossible to complete. Lately they seem to be "a joke". It is time to go for the 120 or 140 pound versions.
The quality of these grippers are superb. If you find the sporting goods version challenging you are not ready for these. If the sporting goods versions are a joke, then get one nearer to the low end to start.
See: http://ironmind-store.com/Captains-of-C ... roducts/8/
These will last a lifetime.
I have also bought their "flying fingers" (lead shot filled bean bags). I've only been using this equipment for a week. I will report after a couple of months' use. I will say that after using it the first time (5 sets; 10 reps) my traps and spinal erectors were VERY tired and the next morning I had "flu-like symptoms" (achy traps and spinal erectors). The flu-like symptoms disappeared after 1 day. This suprised me as I've been doing upright rows for years and the bean bag throw/catch is nearly the same movement. This goes to prove that "fast" training (reps where your body moves quickly) is greeted by your body differently than slow training.http://ironmind-store.com/Flying-Finger ... info/1449/
(Looks like it will last a lifetime. Gotta give it a bit of use before I say so.)