Develops isolated finger strength, flexibility and coordination as it builds hand and forearm strength. Use each button independently to exercise fingers or compress the entire unit for complete hand and forearm strengthening. Comes with illustrated manual. Color Coordinates as follows: Yellow - x-light - 1.5 lbs finger / 5.0 lbs hand Red - light - 3.0 lbs finger / 10.0 lbs hand Green - medium - 5.0 lbs finger / 16.0 lbs hand Blue - heavy - 7.0 lbs finger / 23.0 lbs hand Black - x-heavy - 9.0 lbs finger / 31.0 lbs hand.