Already the second of its kind, only smaller and weaker

Had initially the Thera-Band hand exerciser XL in order for my friend in medium strength (green), currently with, say after about two weeks time distributed on average 4 hourly kneading units throughout the day, he now wants to have stronger hand coach.
But it's here at the normal size hand exerciser, so after several hourly Knettests the XL rubber ball my friend with breaks in between understood I have is for the red (light) Thera Handtrainer entschieden.Dieser for me because I have slim hands exactly richtig.Denke me that the yellow (weakest) for people who have very little power in the hands or health Ursachen.Aber as often happens, everyone has to find out for themselves what / it is pleasant and right for them ,
What bothered me a bit, the rather high price for such a small rubber ball was but if he should now survive for some time (to be seen), it is also worth the money.
Because of the glue, yes it's true, my friend kneads his XL rubber ball also contact stress management quite intense and it can sometimes happen that the ball seems a little tacky, I have then as already mentioned him bag in a freezer along with some cornstarch put a little shaken and lo and behold, everything is back to normal.
Do not quite understand why but some do not get here this problem by gluing under control.
So far we are both very happy, this Thera-Band hand exerciser strengthens the muscles in the hands, fingers, forearms, is also good in bad veins (eg in blood samples, by kneading the blood comes to boil,) and good Last but not least you can get whatever his stress, anxiety quite well under control by kneading this ball.
And yes, you can be addicted to it.