If you just need one set of weights that offers different options and does not take up a ton of space. These weights instead of a bunch of weights cluttering up the place you get two dumbbells with lots of different weights. Please check the SIZE CHART options carefully to see how much weight you want in a single weight. The 40lbs(20lb each weight) are 4 In 1 adjustable dumbbells, this 40LB Dumbbells consists of 8 weight 2.3lbs dumbbell plate, adjustable range is 6.2lb, 10.8lb, 15.4lb, 20lb each weight (A Pair 12.4lbs 21.6lbs 30.8lbs 40lbs). The mechanism to connect and disconnect the additional weighted pieces are simple to use and twist into place, can be quickly to adjust for more or less weight. The weights are square and not round. The square shape keeps them from rolling around on the floor or shelf. The handle boasts anti-slip strips to provide better gripping. These dumbbells adjustable weight is made of tough ABS materials. They are very sturdy and it doesn&