Thera-Band Resistance Bands are one of the most trusted resistive exercise systems on the market; this system includes latex/elastic exercise bands that come in 8 color-coded levels of increasingly more challenging resistance. The idea is to work up from the lightest resistance level (or your individual starting resistance level) to tougher resistances as your workouts progress and you get stronger, leaner, and more flexible. With Thera-Band Resistance Bands, measuring progress and achieving goals for fitness or therapy is easier than ever. Different resistance levels are determined by the thickness of the band. This “Progressive Resistance System” was designed with color-coded levels increasing in difficulty starting at tan (extra thin) and includes yellow (thin), red (medium), green (heavy), blue (extra heavy), black (special heavy), silver (super heavy) and gold (max heavy). This comprehensive system provides positive reinforcement and feedback for gauging results.