Designed to provide soothing and stimulation for sore gumsTeether combines 3 different textures - soft, medium & hard - for each stage of teething. Soft/cold water-filled area is for a young baby (3 months) when first aggravation appears in mouth in order to sooth sore gums. As baby gets older, a harder surface (the tail section) is more suited for a chewing action. Designed to be cooled in refrigerator