this be a superb product . first - unfortunately Amazon do not have the best deal . you can get it at target or Walmart for $ 20 . that be say , this be easy to do at work - I be able to pick it up and use it while I be read or do other thing that would not require my hand . like the commercial say the difference for this weight be that it be use small muscle unlike weight lifting that bulk up you arm . if you have trouble with neck or shoulder you may want to use caution with some of the exercise just like you would if you go to the gym . do a exercise you have not do before should be do with caution and if not do properly could result in a injury . this would be unlikely with the shaker weight but in my opinion anything 's possible . also note-this do not shake on it be own - that be the point of this product that you use you muscle to make it shake . there be review on here that give poor rating because they think it be motorized or something - well , I would say if you do not want to work out and actually use you muscle then you can save yourself $ 20 and do not buy this product : -rrb- it be a great invention and the science behind it make sense . I have see result and I recommend it to all my friend and coworker .