It's not every day that you come across a workout that's endorsed by the Miami City Ballet. But after watching their strength and conditioning coach Michelle Khai twist and turn her way through a an aerobic workout - with a kettlebell in hand - Kettlenetics won over the entire company of dancers. Khai says the product not only increases flexibility in women, but it also sculpts the long, lean muscles that ballerinas are known for. Kettlenetics is a series of three weight-loss workouts that rely on a 4-pound kettlebell and seven signature movements targeting every muscle from your thighs to your core to your shoulders. Khai says the resistance caused by the kettle bell promotes muscle toning, while the aerobic workout results in weight loss. But just how solid are her claims? It's true that training with a Kettlebell can burn up to twice as many calories per minute as most aerobic activities. But in this case, it's really the overall total-body workout that makes the biggest difference, especially since it's not your boring run of the mill routine. One thing to think about before buying this product: Since Kettlenetics relies on just a 4-pound weight, there's little room for you to challenge yourself as soon as you get the hang of the routine. But for just $30, Kettlenetics - with its 20 to 40 minute aerobic workouts - will provide a worthwhile workout, especially if you have trouble making it to the gym. To learn more about other fitness products you've seen on TV, check out other videos in this series.