The perfect sized waterbottle is here and its the Hydro Flask 21 oz standard mouth waterbottle. The 21 oz Standard Mouth is one of Hydroflasks best selling vacuum insulated water bottles because of its size and versatility. It keeps your cold drinks cold for up to 24 hours and made of 18/8 pro grade stainless steel so it can take the bumps and drops of everyday use. The 21 oz Hydro Flask comes in a large variety of colors including favorites like white, pink, lilac, and blue. Looking for a wide mouth version of this bottle? Check out the Hydro Flask 20 oz Wide Mouth Bottle