Insulated tumblers these days generally come in two varieties, plastic and steel. Both kinds of tumblers occasionally have lids that allow you to seal the contents inside to prevent spills or the entrance of insects.
One advantage insulated tumblers of either plastic or metal will have over conventional tumblers is in the area of water rings. Because of the insulation, the outside of these tumblers won’t get hot or cold in response to the temperature of the liquids within. Therefore, in hot, humid climates tumblers with insulation tend to condense less moisture out of the air which reduces and in many cases completely eliminates the problem of water rings.
Many people who prefer iced tea as a beverage also prefer tumblers with sealable lids over conventional travel mugs. The main difference in many cases is the lack of a handle and a narrower, smoother shape which feels more comfortable in the hand when held without a handle.
Some of the new generation of insulated tumblers come with a silicone gripping pad to provide a comfortable, positive grip. Some of these tumblers will be more durable than others. The common plastic variety are slightly less durable, but are available in many colors and designs and are also available almost everywhere. The metal variety are much more durable, and have the added advantage of being inert to any beverages placed inside, which prevents the tumbler from taking on the odor of commonly consumed beverages.
Steel also offers the advantage of not leaching any chemicals into the contents. If you are only interested in plastic tumblers, take heart. Many plastic tumblers are now being marketed that are made of stable plastics that do not include Bisphenol A and some of the other chemicals that have made the news lately. This change makes plastic tumblers once again a viable alternative to metal, but when shopping for tumblers, be certain to check the manufacturer’s description to see if the type of plastic is listed. Manufacturers who are using the new stable plastics will generally say so in their descriptions. If no such statement is made, the tumblers could have either the new or old plastics.