Chinese Hand Exercise Ball
These are called boading balls. It's Chinese tradition for hand exercise. It's relaxing to rotate them.
- Don't buy those with decorative inlaid brass wire (called Cloisonné) on the ball surface. They look pretty, but if you dropped the ball, the metal wire may stick out.
- Don't get those that chime. It's annoying when you use it at office or when people around or family sleeping.
- Do get a bigger ones. For male, get 2 inch (5cm) diameter ones. For female, 1.5 inch is fine. That may be hard to twirl around your hand at first, but after a while, smaller ones is annoying.
Review of Metal Balls
This one is the best. But most expensive.
Crystal ball, quartz ball, or gem stone balls also work. You just have to find the right size.