In reply to Philo22:
There are dozens of threads and articles about this. My recollection from reading them is that gyroscopic balls are useless for finger strength, and hand grips not much better.
In training of any sort, one of the fundamental concepts is specificity - training a specific movement will improve performance
for that movement. Neither gyroscopic balls nor hand grips really mimic any of the typical stresses your muscles suffer when climbing, so they aren't going to be much help.