That, sir as you probably already know is an Ivanko gripper since you bought it. I have one and I have to say I don't like it all that much. It's mainly a question of taste on my part. No criticism implied on your judgment. You can get a chart to incrementally load them by adjusting the springs. Just look up Ivanko and frankly I can't remember the rest but a few tries with things like spring adjustment ought to do it. My beef with them is the increments the adjustments produce are from 1-4 lbs. The variability drove me crazy.
But indulge me and let me ask you this question. What are your goals and objectives in grip training? I do some myself and it's based around the martial arts I do to be able crush the various and sundry danglies the human body has, or the trachea, or pinch grip and rip some even slightly loose skin to produce a cattle prod-like shock to disrupt the CNS and attention momentarily for some follow up. So I do pinch grips and claw grips. The latter with some webbing I got from Ironmind. I can load incrementally a pound at a time and both work quite well for me. Ironmind has some good grip tools that I think can meet any objective you have. I'd suggest thinking over why you want this grip and what you intend to do with it. John Brookfield has some good books on the subject.
Hope this was useful.