The 3-1-1 rule for liquids in carry-on baggage isn't actually called the 311 rule. It's called the 3-1-1 rule because of the three parts of the rule:
- 3: The liquids must be in containers that are 3.4 ounces or less.
- 1: All the containers must fit into a single, quart-sized, clear, resealable bag (one bag per passenger).
- 1: Only one bag is allowed per passenger.
This rule helps passengers easily remember the restrictions for carrying liquids on airplanes.
It's easy to see how the rule got its nickname, 311, as the numbers succinctly describe the rule's limitations.
