If you go online, you'll find a bunch of videos where people take a "pull" of this type tester. This one provides a ton of resistance, but easy to put your fingers around and squeeze the handle.
It's a way test your grip. About 5 yrs ago, I tested one of these and my right hand pulled 129lbs and my left pulled 105lbs.
Today, I have a disability in my muscles and joints, but I did a pull and only got 111 on my right and 98 with my left.
I am using some hand strength work out equipment, so I'll be using this to test how it's going.