I wanted something to strenthen my wrist for tennis and the sports chalet guy showed me this. He got it started for me and it seemed so easy, fun and really a good workout...HOWEVER, getting this home and watching 4 videos, all on youtube bc the software that comes with it didnt work, I still can't figure out the exact rhythm, all i know is sometimes it works, but most of the time nothing...i thought my ball was bad until i read some other reviews about it being so difficult to start... not woth it, very dissapointing...