This is our very first product. We actually put seven other products together (six different balls and a pencil box) and packaged it as our Box of Balls. That was more than 8 years ago, as of this writing, and it is still a big seller.
We originally did this for Bernice, after she broke her wrist. Once the cast came off, she needed to move her hands and fingers to rehab her wrist, but was babying it instead. The balls, in various textures, sizes, and degrees of squeeze-ability did the trick.
We have video of the first time we gave this to her. She spent more that a half and hour investigating each ball in turn, then was ready to begin again.
This box full of colorful balls is one of the early toys we brought to Bernice. She had broken her wrist and the cast had been removed recently. She was reluctant to do anything that was even moderately therapeutic to get back the use of her arm and hand. When we first sat down with her new toy, she was very tired; her speech was soft and mostly incoherent. It was afternoon (not late), and she did tire easily, but that was her go-to excuse when she was unsure. Once she got started she was fascinated. Thirty-five minutes later we had to put them away. She was no longer tired, and she was much more conversational than when we had started. And even she recognized the benefit squeezing these balls had for her mending arm.
Here are some interesting links for you! Enjoy your stay :)