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).