For travel or at home the Fit Tubes are a great and efficient fitness and rehab tool, for toning and strengthening of your body. Fit Tubes are equipped with padded rotator handles for maximum training comfort. They can also be used in group exercises and health and fitness clubs. Which resistance level should I use? Yellow (Light) - Rehab, Seniors and Children Green (Medium) - Average Women Pink (Strong) - Average Men and Active Women Purple (X-tra Strong) - Advanced Men and Women