The 3-1-1 Bag Rule helps travelers carry liquids through airport security without delays. It allows liquids, gels, creams, and aerosols in containers of 3.4 ounces (100 ml) or less, all packed inside one clear, quart-sized resealable bag. Each passenger is allowed only one such bag in their carry-on luggage. Items like toothpaste, shampoo, lotion, and liquid cosmetics must follow this rule. Larger containers should be packed in checked baggage unless they qualify for an exemption, such as medically necessary liquids or baby formula. Following the 3-1-1 Bag Rule makes airport security screening faster and easier.