Since 1991, the innovative PowerBlock range of products that started with the 'selectorised dumbbell' have helped thousands of users. Power Block created a system of quick change dumbbells that are the most versatile and effective system for convenient home strength training.
This has now been applied to kettlebells and to barbells too. It's beautifully simple as instead of having to own a huge range of different sized dumbbells in your home, you simply buy a set of PowerBlocks. Each set has one handle that fits quickly and easily inside the first weight. As you want to add more weight, you just fit that inside the second weight, which fits inside the third, and so on.