Rubber Washable Perfect for rehab, prehab and activation drills. Four levels of resistance Micro Bands are essentially power bands that are smaller in diameter and thickness and best-suited to rehabilitation and prehab work, along with activation drills. They are essential to an appropriate mobility kit, and available in four different resistance levels that accommodate a wide range of athletes and needs. There are four different resistance levels that accommodate a wide range of athletes and needs: Yellow - Extra Light Resistance - 250mm x 50mm x 0.5mm thick. Blue – Light resistance – 250mm x 50mm x 0.85mm thick. Red – Medium resistance – 250mm x 50mm x 1.0mm thick. Green – Heavy resistance – 250mm x 50mm x 1.15mm thick. Black – Extra heavy resistance – 250mm x 50mm x 1.4mm thick If you're chasing a set of four, you can purchase them here at 20% off.