A bottle is a container with a neck that is narrower than the boy and a "mouth." Bottles are often made of glass, clay, plastic or other impervious materials, and typically used to store liquids such as water, milk, soft drinks, beer, wine, blood, cooking oil, medicine, shampoo, ink. A device applied in the bottling line to seal the mouth of a bottle is termed a bottle cap (external), or stopper (internal). A bottle can also be sealed using induction sealing.