Double Wall Vacuum Insulation: Each Hydro Flask® bottle contains a vacuum seal between two walls of food-grade 18/8 stainless steel. This patent-pending double-wall vacuum insulation means that the temperature outside a Hydro Flask® has a very hard time affecting the temperature of whatever you might put in it. Your hot liquids will stay hot for up to 12 hours, and your cold liquids will stay cold for up to 24. The best part is that this is a two-way street; whether you've got hot or chilled liquids inside of your Hydro Flask®, the internal temperature won't affect the temperature of the container in your hand. That means no blistered fingers with your daily cup of Joe, and no troublesome sweat rings-from your bottle of ice water.

18/8 Stainless Steel: At Hydro Flask®, all of our bottles are manufactured using 18/8 "food grade" stainless steel. 18/8 stainless steel is the preferred material wherever food or beverages are concerned because it does not affect flavor, either by adding any metallic taste of its own, or by retaining any flavor from the previous foodstuffs with which it came into contact. 18/8 stainless steel has a non-porous surface that inhibits the growth of bacteria. Bacteria, which are the cause of odors, like to cling to porous surfaces where they can thrive. At the first sign of soapy water, any bacteria that have dried onto the surface of 18/8 stainless steel are swept cleanly away. Hydro Flasks® benefit from all of the superb qualities of 18/8 stainless steel, so you'll never have to worry that the hot coffee you took for your late-night lab session will stain your bottle or ruin the taste of your ice cold milk the next day.

BPA Free: Every Hydro Flask® product is 100% BPA-free. Hydro Flask® bottles are constructed from uncoated 18/8 stainless steel, so there is no danger of a liner getting scratched and releasing the toxic chemical BPA into your beverage. Consequently, your Hydro Flask bottle can keep hot liquids hot without the leaching chemicals that may occur with plastic bottles and aluminum bottles.

No Sweat: Even when packed with ice cubes and water, the double-walled vacuum insulation of the Hydro Flask® will keep it from sweating.