One of the most valuable recovery and conditioning exercises is the use of dexterity balls (aka baoding balls). If you are looking for a low impact, low stress exercise to help stimulate blood flow and work all the small muscles in your hands while also making them more dexterous, look no further. Dexterity balls are unparalleled in their ability to speed recovery from chronic hand pain resulting from aggressive grip related training. No hand should be without them.
We have balls of solid steel and the size is 2-3/8 inch Approximately 60mm.