Meet the Spin Strong Speed Trainers: an exercise tool that uses air resistance to help you get an explosive workout. It is like using a jumping rope but lets you push your body a whole lot more. With complete freedom of movement, you can use these with a range of arm spinning exercises.
These spinners let you perform jump rope, overhead, figure 4, 45-angle, figure eight, and a whole host of other spinning exercises to work your arms. You can find out more about it here.