The quantity of liquids that travellers may bring in their carry-on luggage when flying by air is governed by strict regulations set out by the Transportation Security Administration (TSA). These regulations were put in place to guarantee aviation security and shield against any dangers. The TSA liquid limit allows passengers to transport liquids, gels, and aerosols in containers that are 3.4 ounces (100 millilitres) or less per item, which is known as the "3-1-1" rule. These containers need to be put in a quart-sized transparent plastic bag. There is a limit of one bag per passenger, and it must be submitted individually for inspection at the security checkpoint.