I can't speak more highly about the quality of these products. I love that I can use my own plates (olympic) to adjust my dumbbells to any weight I choose, as small as 0.5kg increments with my fractionals. I never really did much work with dumbbells before I purchased these, always stuck with kettlebells. But I'm completely converted now. I was always out off my a large part of the dumbbells sticking out past the actual weights, but the Adjusta-bells have a nice, tidy end that screws right into the handle and holds the plates very securely. The ends are suited to standard plates (1inch), but with the Centering Adapters even olympic plates fit so snug with no movement during exercises. They may seem a kittle expensive at first for a set of dumbbells, but trust me, if you have the plates at home to attach, or even at the gym, you'll never think about another pair of dumbbells. These are all you'll ever need, and you won't regret the purchase, you'll love them.