Hand Grip exerciser

I am in need for a well-designed well-made hand grip exercise.  I have one that is designed to operate independently, with a spring and finger rest for each finger.
I wore it out. This particular model came in three different strengths.
I don't remember where I ordered the one I have which I've had now for about five years.

Can anyone help me locate a good grip exerciser that comes in different strengths.

Thank you. Merry Christmas to all, Ed

I have several laying about the house and office for bullseye grip strength and for some therapy from injury.     

http://www.amazon.com/Strengthener-Exerciser-Equipment-Arthritis-Strengthening/dp/B00JVR21FU/ref=sr_1_5?ie=UTF8&qid=1451066661&sr=8-5&keywords=finger+exercise

http://www.amazon.com/FlexEx-0001-Finger-Forearm-Exerciser/dp/B00596VWHK/ref=sr_1_1?ie=UTF8&qid=1451066713&sr=8-1&keywords=flex+hand

http://www.amazon.com/CanDo-Theraputty-Exercise-Material-6-Piece/dp/B001763OS6/ref=sr_1_1?ie=UTF8&qid=1451066728&sr=8-1&keywords=hand+exercise+puddy

http://www.amazon.com/NSD-Power-Essential-Gyroscopic-Exerciser/dp/B007GGCLK8/ref=sr_1_1?ie=UTF8&qid=1451066740&sr=8-1&keywords=powerball

I have the Dyna Flex PowerBall and I can recommend it. Here is a link for several of their products: http://www.dynaflexpro.com/products-everyday.html

Gentlemen

Thank you so much for your Quick response and help. I believe I've found just what I need. Happy new year, Ed

A friend of mine is a sports physical therapist, she recommends a balloon filled with sand.  She claims it works as well as the special made machines.

Five Below stores carry a gyro ball for $5. I cannot tell a difference between my branded and unbranded models.

I use these:

http://www.amazon.com/Hotrose®-Silicone-Resistance-Strength-Exerciser/dp/B00RWYM1PO/ref=sr_1_18?ie=UTF8&qid=1451755621&sr=8-18&keywords=hand+exerciser

Joel

FYI go easy on the Dyna Flex ball. I overdid it with one & gave myself pretty bad tennis elbow. It made shooting really painful & limited for a couple of years. After much PT I'm finally getting scores & endurance back where they were before the injury.