A quart-size bag for TSA "3-1-1" liquid compliance in 2026 is a clear, plastic, resealable bag that typically measures approximately 6 inches by 9 inches (15 cm x 23 cm). To a traveler, it looks like a standard "Sandwich Bag" or a small "Ziploc" bag. The key requirement is that it is see-through and has a secure seal (either a "press-to-close" or a "sliding zipper"). The TSA requires that all your liquid containers—each of which must be 3.4 ounces (100 ml) or less—fit comfortably inside this single bag, and the bag must be able to close fully. While many travelers use common kitchen bags, you can also purchase "TSA Approved" toiletry kits made of heavy-duty clear TPU or PVC that have a flat bottom, which are often easier to pack. In 2026, as airports move toward advanced 3D CT scanners, some locations (like London Heathrow or certain lanes at LAX) may no longer require you to remove this bag from your luggage, but the "One Quart" volume limit remains the standard international rule for what you are allowed to carry onto the aircraft.