Thera-band Latex Exercise Bands are available in eight color-coded levels of resistance. Proper use of these systems for resistive exercise provides both positive and negative force on the muscles improving strength, range of motion and co-operation of muscle groups. Progressive resistance gives at-a-glance documentation of progress from one level to the next. Features Thera-band Latex Bands Exercise System is portable and versatile with virtually unlimited uses Designed with color-coded levels increasing in difficulty from Tan extra thin to Gold max Different resistance levels are determined by thickness of the band Measuring progress and achieving goals for fitness or therapy is easier Endorsed by the American Physical Therapy Association APTA 1 Each / Each