Love to use these when I'm sitting at a red light forever or when I'm at work and don't have anything to do. The mesh bag that they come with keeps them in line and basically the Chinese really know how to give your hands a work out. I put these to use before I head out to climb to loosen up my hands. If you have smaller hands, like myself, they're a little difficult to use at first.
Pulled a muscle in my hand and used these to nurse my hand back to health. Worked excellent, hand healed a lot quicker than it normally would have. Don't drop them because they can scratch, dent, or chip, they still work great though. Good mindless excersise to occupy time while loafing.