No doubt the CoC grips are great, but they're spendy.
A buddy who arm wrestles turned me on to the Iron Woody grips.
https://ironwoodyfitness.com/product/the-woody-gripper/
Adjusts from 45-345# and costs 25.00
He suggested doing 15 squeeze reps, then to squeeze, hold, and bring your wrist in 90° and hold for 15 seconds,doing three sets.
I've been doing it for a couple months and noticed considerable increase in grip strength.