Also known as vacuum flasks, these are essentially vacuum insulated liquid storage containers which allow the content to remain hot or cold irrespective of the surroundings. The original design was invented by Scottish scientist Sir James Dewar for his experiments and it later became a household item to keep liquid warm and cool for a specific duration. They are used domestically to carry beverages like tea or coffee, soup, milk and cool drinks.It may not be possible to reheat or refrigerate liquid while outdoor. Thermos flasks help you quench thirst anytime and anywhere without compromising your hot and cold preferences. A typical domestic flask can keep liquid cool for about 24 hours and warm for up to 8. Conventional flasks are made with stainless steel. Modern designs are available in plastic and polypropylene. They also include induction bottom and microwave safe features for easy food processing.A flask can be used to carry your morning drink while on the way to office or to take cold water with you while out jogging. Having your own thermos flask helps to maintain your daily liquid regime. There are a variety of flasks available for purchasing, but choosing the right one should be according to the quality and purpose. While the thicker ones are more efficient in retaining the temperature and are ideal for long duration storages, thin flasks can get damaged when hot water is poured frequently.