Finger Resistance bands are very safe and can be used by anyone without the fear of heavy equipment causing any damage. Even if you are not suffering from any pain in your hands and fingers a hand strengthener can be used at all times as it will make your hands and forearms stronger for other forms of exercise.
How do you use finger resistance bands?
https://www.youtube.com/watch?v=y0WbmQp4XbM
Do finger stretchers work?
The emphasis on “strength” that comes from these finger exercisers might not just be inefficient though; it could jeopardize your guitar playing future. As Digital Music News notes… “The reality is that most players don't improve their playing or dexterity with squeezing types of hand exercisers.