The product uses food-grade Wacker silicone from Germany, which has good elasticity and tension and is lighter and more resistant to dropping. It is more hygienic to chew and can be sanitized through pasteurized high-temperature boiling, ultraviolet light, etc. Different silicone softness has been creatively used to fulfill the baby's needs at various stages of teething. For babies with sensitive gums, the 30 degree softness with great elasticity is best, while the 50 degree softness can satisfy the requirement of gnawing, no tearing. The two massage heads' softness can be chosen at will. The safe material complies with environmental-friendly criteria because it doesn't include bisphenol A, PVC, phthalates, and so on, which can be recycled and also has no chemical penetration.