I be surprise to see this item have positive review . I be happy that it apparently do work for some people . however , in my opinion , it be just another gimmick . shake you way to more muscular arm use something so light ? yes , you might feel something -lrb- and be careful that it be not pain due to injury that you be feel ! -rrb- but you can do this type of exercise use just about anything of the same weight -lrb- whether it be a water bottle or a can of soup , etc -rrb- . I do try this product and , personally , I recommend good old fashion push-up instead . specifically tricep push-up if you be aim to work on toning\/defining that `` under the arm '' area -lrb- below you biceps -rrb- . you have three different muscle in you tricep area -lrb- thus , the name , as `` tri '' mean `` three '' -rrb- . it be not logical to use a light weight dumbbell and `` shake '' you way to definition\/strength of all these muscle . nose crusher and dip be a few other exercise that be great for the triceps . this area can be a problem area for both man and woman but from my experience , more woman seem to be bother by it . dip would be perfect for woman who do not want to develop a more `` bulky '' appearance as you use you own body weight against you while nose crusher would be best for man as you can use the weight of you choice and keep increase it as you progress . -lrb- please note : dip be a common exercise , as be Nose Crushers , but Nose Crushers MIGHT be know by a different name by you personal trainer -rrb- . of course , tricep push-up be very effective for both sex . one of my main reason for be unhappy with this product be the very high risk of injury that can be cause from do these exercise . not just the chance of pull a muscle , but it also increase you chance of head , neck and shoulder injury -lrb- which take forever to recover from -rrb- . tricep push-up , dip & nose crusher be excellent exercise for the tricep muscle that do not have a high risk of injury to any of these area -lrb- with the exception of nose crusher - if you do not have a spotter and do drop the barbell on you nose , well , like the name of the exercise state , you nose will be crush ! -rrb-