2. Size: The size of the grinding bar should be suitable for the child's age and oral size. Generally speaking, the diameter is between 3-6 cm.
3. Shape: The shape of the grinding bar should be diversified, with different shapes such as circle, square and triangle to attract children's attention.
4. Color: Colors should be bright and bright to attract children's attention.
5. Brand: Choose famous brands of grinding bars, and the quality is guaranteed.
6. Price: The price should be moderate, not too expensive or too cheap.
7. Packaging: Packaging should be exquisite and easy to carry and store.
8. Word of mouth: You can check the comments and recommendations of other parents to understand the quality and use effect of the products.