Vacuum Insulated: The Simple Modern Ascent water bottle is double wall and vacuum insulated. This technology keeps your beverage hot or cold for hours. Specific details for each size are listed in the description and the featured photos. No need for koozies or coasters! No matter the temperature of the liquid in this bottle, it will never sweat or be hot to the touch. Straw Lid: All Ascent bottles in this listing come with the straw lid. This straw lid is leak proof, with a nozzle the flips up for easy drinking. This lid is great for kids and adults at home or on the go. The opening on every Summit bottle is the same width so the same straw lid fits an size of bottle. 18/8 Stainless Steel: This reusable bottle is made from premium gage 18/8 stainless steel. This material is BPA free and will never rust or leave a bad metal taste in your mouth. This product is not dishwasher safe but the wide mouth makes it easy to clean. 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. Narrow Mouth: The Ascent's narrow mouth provides extra insulation. The opening of the bottle fits most ice cubes.