Preferred choice of therapy and fitness professionals. 2 levels of bands included. Fitness products for healthy lifestyles. Two levels of heavy resistance training provided in this kit. The choice of rehab and fitness professional worldwide. Band Color: Yellow, Workout Level: Beginner. Red: Beginner/Intermediate. Green: Intermediate. Blue: Intermediate/Advanced: Included. Black: Advanced: Included. All bands are 5 ft./1.5 m. in length. Training guide included. Product endorsed by American Physical Therapy Association.