I purchase these dumbbell fairly recently because I want to use they for Chalean Extreme -lrb- you can check out the program at Beachbody dot com -rrb- . I have be lift weight for several year , but have mostly be do high-rep , low-weight workout -lrb- to give you a idea , the heaviest dumbbell I own be eight pound -rrb- . because I want a variety of weight and have very little room , I decide to get a set of adjustable dumbbell . I do quite a bit of research on all the various brand before I decide on the PowerBlocks . so far , I be really please with my purchase ! these dumbbell be easy to use , feel very balanced , and take up very little room . the only bad thing about they be that they be fairly expensive . however , if you add up the cost of buy a pair of dumbbell for eight different weight -lrb- 3 , 6 , 9 , 12 , 15 , 18 , 21 , and 24 lb -rrb- , the price seem much more reasonable .