Featuring our TriMax triple insulation technology, the BOULDER and BIGFOOT have been tested to keep water cold for up to 36 hours and hot 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. These Eco Vessel bottles have a wide mouth to easily accommodate ice cubes and a comfortable, convenient drinking spout. We've also included a removable tea strainer/ice dam. The Boulder and BIGFOOT are sturdy, high quality, stylish vacuum insulated steel water bottles for the office, tennis courts, golf course, on the trails, anyplace, anytime.