Want to utilize your Pilates Power Gym to strength train and build more muscle? The Pilates Power Gym Extreme Power Resistance Cords procvide an additional 25 resistance levels of enhanced resistance to you Pilates workout. It"s like adding a whole new set of weights to your Pilates Power Gym. These four Extreme Resistance Cords are fully compatible with the Pilates Power Gym PRO and PLUS models and instal in just minutes.