The Hydro Flask Standard Mouth 21 oz is ideal for taking on the weekend bike ride or hike to keep your fluids cold. Or take it up the mountain and have coffee, hot cocoa, or soup waiting for you at the end of the day. The standard mouth features a larger opening than our original narrow mouth bottle. It is ideal for coffees, teas, mixing sport drinks, or just for those who need to take in more hydration, more quickly. As with all Hydro Flask bottles, they fit perfectly in most car, bicycle, and stroller cup holders and water bottles cages. Hydro Flask Stainless Steel water bottles were developed to perform in every environment.