The Nüobell 232 "dumb"bells have nothing dumb! They are really smart, efficient and convenient! They save space, they allow you to practice every muscle with its own weight (e.g. shoulders vs. biceps), and they look good!
The whole family can even train with them ;-) If you want something to improve is maybe the rough angles (although I would not know how to improve this without disrupting the perfect design and balance): they hurt when I'm doing hip thrust with one dumbbell on my stomach. I need to use a pillow.