Have now 2 worn by the parts. I find these things quite handy basically because they are very small. One can the coach virtually always carry in your pocket and the finger exercise. After a while, even sets a noticeable success. At first I did about 150x squeeze the piece done .... now I hear at 600 to count. Have the tots almost always in one hand, if I have it free (at work, by the way when I see a movie). However, the devices wear out rather quickly. Well, I will turn the thing practically the whole day together .. frequency to "Produkttod" should be in the high 5-digit range. In the last third of the "shelf life" you have already noticed that the thing starts to squeak, and increasingly unstable and shaky was. Meanwhile, 2 springs are broken, and many plastic parts are completely worn out and scraped. If one uses the part now and then, it's really convenient and useful to bring the finger muscles into shape (primarily is thus the endurance and less strength training). "Permanent" use but not tolerate the part. If here and there a bit more metal would be installed ........
