Theraband Tubing, Yellow, 100 Feet, Dispenser Box Tubing Is Made Of Natural Rubber. Resistance Levels, Obtained By Varying The Thickness Of The Thera-band Tubing, Are Color Coded In Proprietary Thera-band Colors Increasing In Difficulty Through Seven Levels From Tan Through Silver. The Color-coding System Provides Positive Reinforcement And Feedback For Gauging Results. Product Photo May Not Exactly Match The Product Offered For Sale. Please Refer To The Product Description.