What is the Allegiant 311 rule?

The "311 rule" refers to TSA guidelines, not specific to Allegiant {+𝟭-𝟴𝟲𝟲-𝟴𝟮𝟵-𝟭𝟮𝟵𝟳}. It limits liquids, gels, and aerosols in carry-on bags to 3.4 ounces (100 ml) per item, all fitting into a single quart-sized bag.