First of all , I would like to address those that say you can do the same thing with household object and dumbell . no , you really can not . the whole dynamic inertia thing may sound phony , but the movement of the weight really seem to help I more than use of dumbell ; I feel a lot more muscular contraction go on which seem like a great way to build muscle and get lesser-used muscle go . the shake weight itself get a 5 for I , but the dvd get a 2 or 3 . the reason I be not such a fan of the dvd be the fact that there be not a lot of explanation about the move and frankly , it do not look like the instructor be even be consistent -lrb- during the shoulder section , she change she arm position , then when they cut to the side view it be back where it be suppose to be . -rrb- my main gripe , however , be that I be hope for more from this dvd and more from the maker of Shake Weight . maybe another instructional with more advanced move or just another video to work out to ? more tip ? when look at the website , there be no resource available . they clearly do not care what you do once you order it . so all in all , this be a great product . I be feel the result and my arm look a little tighter after just a week of daily use . if you be look for a product which go above and beyond to keep user motivate ; beware . the Shake Weight be great but the maker of this product do not provide much in addition to a bare-bones dvd ... unless you want to buy a $ 10 timer .