Level 0 (Beige) Beginners, stroke patients, persons with serious hand injuries, establishing range of motion. | Level 1 (Yellow) Children, geriatrics, beginning strength programs, athritics, carpel tunnel. | Level 2 (Red) Most popular for all around use - such as strengthening, flexibility, injury rehabilitation, sports, fitness. | Level 3 (Green) For more advanced rehabilitation, sports, strengthening, fitness, injury prevention. | Level 4 (Blue) Sports strengthening for all major sports - for those that want to build real strength, very popular for pro sports training. | Level 5 (Black) A real challenge for advanced strengthening, used where hand strength is vital - such as karate, weight lifters, golf, baseball, football. |