Modern Adjustable Dumbbells
Powerblocks was one of the most popular adjustable dumbbell on the market. But they're awkward to hold and may limit you in some exercises. The SMRTFT Nüobell on the other hand looks more like a traditional dumbbell. There's no overhang for any weight that you choose, in this case from 5 – 80 lbs, which means you can rest it on your thighs without it poking you. And it won't interfere as much in your movements.
To change weights is very quick too. Simply twist the handle towards the “+” or “-” sign to the desired weight and lift. There's an indicator to tell you what weight is currently selected. There's no need to remove pins and reinserting them like in some adjustable dumbbell systems.
The Nüobell is sold in pairs and come with a cradle. They're quite expensive though at $745 per set. A 50lb set is also available for $595.