The glass material is clean and colorless, has high light transmittance , and is easy to check. The surface is very smooth, easy to wash and not easy to scratch and leave marks. The heat resistance is the highest of all materials at present , reaching about 600°C. It is heavy and fragile , so it is suitable to be placed in the home or fixed place. It is not suitable for babies to practice grasping by themselves, and it is recommended to be used by parents when feeding.