TheraBand Professional Latex Resistance Bands for Upper and Lower Body Exercise A superior band product for resistance training and rehabilitation, provides both positive and negative force on muscles and joints, stretches tones and conditions all major muscle groups Improves strength, range of motion and flexibility in a simple to use, portable product that works in the clinic, the gym, at home or on the road Color-coded Progressive Resistance system allows users to recognize improvement as it happens, as you grow stronger you can move up to the next color Highest quality natural rubber latex resistance bands are recognized as the original system of progressive resistance for over 40 years Extra Heavy Blue Bands are the fifth of eight levels of resistance and great for rehabilitation and moderate to high resistance exercise, they offer 5.8 lbs. resistance and 25% increase from preceding color at 100% elongation and 8.6 lbs. at 200%