so , I be walk through Dick 's Sporting Goods and see these weird look adjustable dumbbell . I want some adjustable dumbbell for a long time but the Bowflex and Weider one have move part that do not seem to work right and look like they be go to snap off not to mention the hefty price tag . so suffice to say I think these be go to be junk too . I try they in the store and go home and sell my home gym so I could buy these . man , do I love these thing . they be sturdy , intuitive , take up next to no space , and use they with p90-x have be awesome ! the fact that the work on a bracket and brace system that do not have spring or mechanical part mean I do not have to worry about they break and get stick . I work as a draftsman so I have a analytical mindset and the more I use these thing the more I think they be design by a real engineer and not some `` product designer '' who want a product that look cool regardless of function . solid as a rock and if use right should last a lifetime . the one I have go from 5-50 and adjust in 5 lb increment . if you need more than 50 lb then they have upgrade set that you can buy but they be kind of costly . do not think I 'll need the upgrade anytime soon . these thing rock ! if you buy they in a store and not on Amazon you might save a little money , too .