A Dewar flask is a specialized container designed to store and transport liquids at very low temperatures. It consists of two flasks, one inside the other, with a vacuum between them. This vacuum minimizes heat transfer, keeping the contents cold or hot for extended periods. Commonly used in laboratories and industries, Dewar flasks are ideal for holding liquid nitrogen or helium. They come in various sizes and shapes, making them versatile for different applications. The design helps prevent condensation on the outer surface, ensuring safe handling and efficient storage of cryogenic liquids.