these dumbbell be excellent ! I use the Bowflex SelectTech adjustable dumbbell and find that they be very bulky -lrb- which may limit some exercise -rrb- and rattle in you hand . the Bowflex dumbbell also need to be line up just right when set they down on the stand , which can be a minor nuisance . the PowerBlocks adjust easier and quicker than they Bowflex counterpart . quality adjustable dumbbell like these may look expensive at first , but they be build very well and will last many many year . I use these for my p90x workout , and in a typical hour workout , I save myself at least 10 minute use these dumbbell over my old custom-weight dumbbell with a fraction of the footprint . you will not be disappoint with PowerBlocks !