AO Coolers Insulated Canteen Keeps Liquid Cold for 16 Hours or Hot for 8 Hours. 26-ounce insulated vacuum thermal bottle with double wall 18/8 stainless steel construction. Threaded insulated lid to keep your drinks cold for up to 16 hours or warm up to 8 hours. Slim enough to fit in standard cup holders. Copper plated inner wall prevents heat from entering or exiting the bottle by thermal radiation.