We added extra insulation for maximum performance. Featuring our Trimax® triple insulation technology, the Boulder has been tested to keep water cold for up to 36 hours and retain heat for up to 8 hours. Perfect for water, tea, coffee, soup or just about any drink. Its tight screw on top will keep your drink securely inside, where it belongs. It has a wide mouth to easily accommodate ice cubes and a convenient drinking spout. The Boulder is a sturdy, high quality, stylish bottle for the office, tennis courts, golf course, on the trails... anyplace, anytime.