With the adjustable dumbbell from Optimum, save space as it allows you to have an entire set of dumbbells in one. You can adjust it from 2.5 to 24 kilograms. It only requires a simple twist of the dial to select the desired weight. It adjusts to 2.5 - 3.5 - 4.5 - 5.5 - 6.5 - 8 - 9 - 10 - 11.5 - 13.5 - 16 - 18 - 20.5 - 22.5 - 24 kilograms.