Adjustable Selectorised Dumbbells are easily changed when resting in a dumbbell stand. This is done by adjusting the number of plates that follow the handle when lifted e.g. by turning a dial or moving a selector pin. The benefit is that you do not need to manually add or remove weight plates or purchase multiple sets. This also makes them very space efficient. The stand also doubles as storage for the additional weights not being used for a particular exercise.