Double Wall, Vacuum Insulated: This bottle has a double wall exterior with a vacuum between the walls. This means your drink in the bottle has no medium for the heat or cold to transfer through. The BPA free stainless steel lid is also insulated against heat transfer. Your drink will truly stay as hot or cold as long as possible. Even filled with ice or boiling water, the bottle will never sweat or get hot to the touch! Premium Copper Coated Insulation: The exterior of the inner wall, in the vacuum sealed area, has been dipped in copper for added insulation. Copper reduces the transfer of temperature, adding even more insulation to your bottle. 18/8 Stainless Steel: This insulated cup is made from premium gauge, rust resistant 18/8 stainless steel. We have chosen from the most popular colors, giving the container a vibrant finish. The solid colors have a subtle sparkle in the paint. This FDA approved will never rust or leave a bad metal taste in your mouth. Leak Proof Lid: Twist the lid all of the way on the bottle to create a leak proof seal. The lid is double wall insulated, adding further temperature retention to your beverage. Cupholder Friendly Sizes: The 9oz and 17oz Wave bottles fit in most cupholders, the 25oz and 34oz bottles are too wide. Narrow Mouth Opening: Say good-bye to spilling your drink on your shirt because of sloshing. The narrow mouth on the Wave bottle will channel your beverage,allowing for easy spill free drinking. Normal sized ice cubes will fit through the opening one at a time. The 25oz Wave will hold a full bottle of wine. Why Simple Modern? The S|M logo stands for more than premium drinkware. At our core, we believe that relationships are more valuable than profit. Generosity is one of our two core company values. We give a minimum of 10% of our profit away and have been able to donate product to natural disaster causes. Simple Modern products are all reusable, reducing waste in our landfills. Our products are designed to simplify your life, empowering you to be a positive impact on the people around you.