This exercise is an example of how cable work has some advantages over a barbell in that the loading curve matches the strength curve, so there's constant tension on the delts from start to finish.
The other advantage is that most of the initiation of the movement comes at the shoulder joint rather than the elbow joint. The synergy between these two components makes this movement an awesome shoulder developer.
For this mechanical drop set, you'll start with the hardest exercise and, as you fatigue, move to the easiest. Works with a bar and a supinated grip too.