this be a excellent product if you want to feel you muscle burn in you arm and upper body in a very short time . you have to learn to not grip the Shakeweight tightly . just let it rest on you palm and shake . there be not that many position for hold it . but then how many different way can you hold and move a dumbbellt ? so start shake and count to 30 . if you can get to 30 in each position , you be do pretty well . if you can count longer , you have get really strong arm . when you hold the Shakeweight in front of you parallel to you body with both hand , you actually work you entire body include you leg since you be shake you entire body . enjoy it ! the Shakeweight be definitely a excellent product and worth the price . and you can feel the heat in you arm for quite some time after you complete you set . it pump you up .