GoFit Smart Weight Power Tubes provide resistance training, which when used in conjunction with cardio training, provide maximum fitness results. The Smart Weight tubes provide the approximate resistance of utilizing a similar weight dumbbell. Power Tubes are a great way to train anywhere, anytime. They will train all of the major muscle groups, with the exception of the abdominal muscles. We recommend using the Ab Wheel for abdominal workouts. Don"t forget your cardio