I have bought the Bow Flex "Select a weight" dumbbells these are the ones that have the rotary dials at each end of the dumbbell so that you can dial in the amount of weight for each dumbbell. The increments are: 5, 7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25, 30, 35, 40, 45, 50 & 52.5 pounds. In order to get all of these separate dumbbells you need the space of a small room to store all of them and a rack to hold them all so you won't trip on them when you walk into the room. By having the selector on each end of your dumbbells you dial in the desired weight that you want to work with and then just...