Airisland Hand Finger Squeeze Stress Balls on a String Grip Strengthening Therapy Perfect for Stress Relief Hand Exercise Arthritis Rehabilitation Set of 3 Resistance Balls No Falling Rolling Away

All the balls are similar in hardness. There is no difference other than color and words that say soft medium and firm.There is no instruction manual of how to use it and makes it quite useless.The way the cord ends are knotted, it looks like it was made in someone's living room.

I suffer from low blood pressure and I needed a stress ball at work to help keep my blood pumping. These were great. The strap keeps them on me so I don't lose them, and the material is sturdy.

I bought these for help with arthritis pain and carpal tunnel. The soft ball is not very soft. Also, there was no instruction sheet on how to do the various hand exercises.