Contrary to popular belief that using hand grippers will increase your wrist, in reality hand grippers do not really increase your wrist size. Your wrist is a joint and contains very minimal muscles, hence their is no growth opportunity present at the wrist compared to your forearms which are made of numerous muscles.
A hand gripper may strengthen your tendons present at the wrist overtime which may lead to thicker tendons which can contribute to added wrist size but the effect will be minimal and difficult to notice actual wrist thickness.
Hand grippers are a great way to strengthen your grip and will help you build bigger forearm muscles, however when talking about the wrist, it's a joint and bones don't have growth potential especially when you're out of your growing phase (which usually stops at 21 for most people).
If you had small wrists like me your entire teen years then I'm sorry to say but you really can't do much about them, your best bet will be to train like arm wrestlers but even then your actual wrist bones getting thick is something unheard of.
However I will say this that building your forearm muscles can contribute to your wrists looking significantly thicker and you get out of your dreaded skinny forearms look. Let me now show you how you can build bigger forearms with the help of hand grippers.
HAND GRIPPER USE
STEP 1
I would suggest for beginners to start with this hand gripper. This an adjustable hand gripper with resistance varying from 10-40kgs.
When I tested the resistance, I found out the max resistance was 25kg and not 40kgs like it claimed but anyway this hand gripper will be a good starting point for beginners who have limited experience with hand grippers.
When you can close this hand gripper for around 20-25 reps at the max resistance of 40kgs (in reality 25kgs) then you can move onto Step 2. Checkout this adjustable hand gripper on amazon
STEP 2
Next move onto this steel hand gripper with a resistance of 150lbs (68kgs) but again when I tested it out I found it is around 40kgs of resistance and not 68kgs like it claims.
But anyway this is a hard hand gripper, as you can see that I cannot completely close the hand gripper (the ends should touch each other). I can deadlift around 150kgs with bare hands so this is quite a hard gripper for me as well.
If you are able to close this hand gripper for 20-25 reps you will have some good development in your forearms. Checkout this hand gripper on amazon
STEP 3
Next you would want to move onto the USI 200lbs hand gripper. This is a very hard hand gripper to close and you won't be able to close this hand gripper even if complete Step 1 and 2.
You would need several months to be able to close this hand gripper and in the process you will build some thick good looking forearms as well.
I think if you can close this hand gripper for 5-6 reps then you would pretty satisfied with your forearm growth. Check it out on amazon below