The bowflex adjustable dumbells are a must have for a home gym with limited space. Rather than needing to buy a full shelf of dumbells to meet all of your excercise needs, this adjustable set can serve as all weights between 5 and 52.5 pounds. All you do is rotate the gears on both sides of the dumbell to line up to the weight you want, pick it up off its stand, and voila.