The GoFit Pro Gym-in-a-Bag is just the ticket to achieving your fitness goals—whether it"s to build size and strength, or increasing muscle definition. The key to the Pro Gym is the ability to add or subtract resistance by adding or subtracting the resistance tubes. There are 3 levels of resistance: light, medium and heavy, and the different colors signify the various levels of resistance. By using different combinations of the 3 various resistance tubes you can achieve 7 different levels of resistance. Regardless of your fitness level, the Pro Gym will help you attain a healthier you! Includes 2 handles, 3 resistance tubes, 2 ankle straps, 1 door anchor, instruction DVD and wall chart of excercises.