These are available from Iron Mind for $18.95 +S&H. They are used to train the crushing aspect of hand strength. I was primarily interested in using these as I do a lot of heavy knife work. I was looking for a way to increase the power of my grip, the strength of my forearm and to increase my ability to handle heavy chopping impacts.
The grippers have aluminium checkered handles which are very secure. This is obviously necessary as it takes a lot of force to close them. There are five models to choose from in terms of resistance :
I am not sure what these numbers refer to. I assume that it is the amount of force that when applied perpendicularly to the bottom of the handles will fully close the gripper. In terms of difficulty, this is what Ironmind has to say about the grippers (from the website) :
Start with our Trainer, which is literally about two or three times the strength of a sporting goods store gripper and work your way up. The No. 1 will stop most guys who lift weights; the No. 2 is rarely closed; the No. 3 has only been closed by about a dozen men in the world (and most of the strongest have tried!); and the No. 4 has been closed by only one man.
When I first started using the grippers I found them very abrasive and had problem with even moderate repetitions. However after a few weeks it was not a problem and after a few months it doesn't concern me anymore. I can now do even high reps sets (25+) without discomfort. One very nice side effect is that many knife handles which used to bother me, don't anymore because my hands have become more resistant to abrasion.
I have seen an obvious increase in my grip and forearm strength as well as in my wrist's ability to absorb heavy chopping impact. This is exactly what I was looking for so I am very happy with them. Note the springs will take a light coat of rust really easy so don't store them in the plastic bags and lubricate them with something that provides decent corrosion resistance as well. I currently use a version of White Lightning offered primarily as a knife lubricant.
You can comment on this review by dropping me an email : cliffstamp[REMOVE]@cutleryscience.com or by posting in the following thread on Bladeforums :
If you are interested in the CoC grippers, which seems likely since you read this review, you would also probably be interested in a review of a similar product from Ivanko
as well as the Gripboard, a dicussion form about grip strength.
If you are seriously interested in strength training you should also check out the following site :