Ask any serious bodybuilder; free weights are hands-down the best tools for increasing your strength and muscle mass. They open up a huge range of exercises and, as opposed to machines,engage a lot of additional muscle groups to keep the balance.Each muscle group requires a different weight, and with your dumbbell, you can select just the right amount in seconds. You can literally put your progress on speed dial. Simply twist the secure lock-in dialand select the desired weight within seconds. Any remaining weights will be left in the base plate.Giving you the versatility of 6 standard dumbbells, your AtivafitÂ® saves you on the initial outlay cost as well as being much more compact to store! With superior design and build quality, it should come as no surprise that AtivafitÂ® are leaders in the U.S. market. While other adjustable dumbbell models have a plastic locking system, AtivafitÂ® employs a secure high-tensile steel design.Comfortable and secure grip control is provided by the contoured soft grip handle design. Make the home of fitness yours today!