I be really excite to get this product , in fact , most of the review on Amazon lead I to believe that this prodcut be worth check out . naturally , I be skeptical and wonder if it would really work . the SW just arrive yesterday and I be really excite to put it to the test ! I complete the 6 minute arm workout which do not sound like it be even long enough to work anything , but to my dismay , my muscle be definitely work ! however , about a hour after my workout I be do my normal odd job around the house when I happen to look up from whatever I be do and it feel as though every single muscle in my neck have be pull . it be and remain horribly painful . I have iced and heated and even go to yoga this evening in hope it would relieve the strain . they do not tell you to relax the neck in the workout and I do not even think I be strain it until the aftermath . please please do not strain you neck or place unnecessary tension in you neck as you figure out how to use this weight . surprisingly , the proper technique do take a bit to get down as you naturally want to move you wrist etc. . I would not say do not buy it ... just buy it and realize that other body part may feel strain from the shake ! good luck in you decision make !