Great exercise to teach the proper form to squat, as the ball between your legs makes your lateral stabilizers activate and not push out to the sides. the dumbbells make for added resistance
in this video it is shown closer to the body which puts more emphasis on the triceps, i would recommend you do it with the arm away from the body to maximize core involvement.
this is pretty good exercise that involves the core muscles as you are only carrying with one side, and it works your back muscles as well as the motion going up