Hydro Flask 21 OZ 621 ml Standard Mouth with Flex Straw Cap is an insulated water bottle that is perfect for any occasion, from the office to outings to the mountains or crags with a convenient spout cap.Made of 18/8 pro-grade stainless steel, it is super strong and guarantees pure taste without flavour alteration. The double-walled vacuum insulation maintains the temperature for hours: cold drinks stay cold and hot drinks stay hot! The bright colours of these bottles are not only beautiful but also functional. The powder coating makes them easier to grip, less slippery and more pleasant to the touch.