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 groupsnImproves 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 roadnColor-coded Progressive Resistance system allows users to recognize improvement as it happens, as you grow stronger you can move up to the next colornHighest quality natural rubber latex resistance bands are recognized as the original system of progressive resistance for over 40 yearsnSpecial Heavy Black Bands are the sixth of eight levels of resistance and great for rehabilitation and higher level resistance, they offer 7.3 lbs. resistance and 25% increase from preceding color at 100% elongation and 10.2 lbs. at 200%nThera-Band exercise bands are low cost versatile and portable 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. Endorsed by the American Physical Therapy Association (APTA), they are recognized worldwide as the original System of Progessive Resistance. Uses for the Thera-Band Bands include: 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.