Shake Weight Men's- 5lb Arm Firming, Muscle Toning Dumbbell, Get Real Ripped & Rapid Results with New Dynamic Inertia Technology, Bonus Workout DVD Included Special pulsating dumbbell for shaping and toning upper body Dynamic Inertia technology ignites muscles in arms, shoulders, and chest Increase upper body muscle activity by 300 percent compared to regular weights Works in only 6 minutes per day; fits easily inside a suitcase or travel bag Instructional "Upper Body Sculpting" workout DVD included High intensity rapid fire muscle reaction Workout your upper body in just 6 minutes a day Uses revolutionary New Dynamic Inertia Technology