NUK Cool All-Around Teether: intensive cooling and massage for teething babies. , , Our NUK Cool All-Around Teether has four cooling elements filled with sterilised water. This means that the practical teething aid can be kept cool in the refrigerator. Cooling the gums can help ease the teething process, but take care: teethers do not go in the freezer compartment! If they are too cold, they can cause frostbite on the lips and inside the mouth. , , Our NUK Cool All-Around Teethers different surfaces ensure variety as well as a gentle massage when bitten. Your babys constant attempts at chewing also activate the saliva flow, which helps to soothe your baby's mouth.