First the bad - When you are doing drop-sets, are shaking and sweating, unable to quickly change the weight on these bad boys becomes an issue. But you can still do it, with sufficient coordination, grit, and a certain amount of swearing. Otherwise, the PowerBlock adjustable dumbbells (Sports EXP) are a serious amount of weight, from almost nothing to half-an-elephant, that takes up the same amount of space as a single pair of dumbbells. Just don't drop them on your toes when your shaking and sweating, racing to adjust the weight while not wearing shoes. I recovered, but still get nervous when repeating it...