Grip Pro Trainer
Grip Pro Trainer is an extremely effective finger-hand-forearm strength and endurance trainer.
Grip Pro Trainer is very portable and easy to use, almost anywhere/anytime - at your desk, stuck in traffic, walking, on the treadmill, etc. Try 3 sets of 10-60 reps a couple of times a week for best results over time. It's also great for stress relief.
Increase reps as necessary.