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Hydro Flask 21oz Standard Mouth Flask

Hydro Flask 21oz Standard Flask
Hydro Flask 21oz Standard FlaskHydro Flask 21oz Standard FlaskHydro Flask 21oz Standard Mouth Flask
MSRP: $27.99
Our Price: $18.19
You Save: $9.80 (35 %)
Manufacturer: Hydro Flask

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The 21 oz vacuum insulated Hydro Flask is our most versatile medium sized water bottle and one of our most popular. With a convenient 21 oz capacity and a 1.81" mouth opening great for sports drinks, thicker liquids or nearly any size ice cube, this is a drinking bottle as diverse as you!

The 21 oz insulated bottle is made from 18/8 food-grade stainless steel and the double wall vacuum insulation provides top notch insulation power, keeping cold liquids icy cold for up to 24 hours and hot liquids steaming hot for up to 6 hours.


  • Standard Mouth Opening
  • Double Wall Vacuum Insulated
  • Keeps Liquids Hot up to 6 Hours
  • Keeps Liquids Cold up to 24 Hours
  • 18/8 Stainless Steel
  • Signature Powder Coat Finish (exception is Classic Stainless model)
  • Lifetime Warranty


  • Weight: 10.4oz / 295g
  • Height (no cap): 8.8in / 224mm
  • Flask Diameter: 2.87in / 73mm
  • Mouth Width: 1.91in / 48.5mm
  • Volume: 621mL

Hydro Flask Care:

Before initial use, hand wash your flask and cap with hot, soapy water. Rinse the flask and cap. The flask is now ready for liquids.


  • Put your Hydro Flask in the dishwasher. The dishwasher can get hot enough to affect the insulation property of the flask as well as discolor the powder coat.
  • Put your Hydro Flask in the freezer. Due to the double wall vacuum insulation, the water inside will be protected from the temperature inside the freezer and wont freeze. If you want ice cold water, put some ice cubes inside your flask and notice how long it takes them to melt!
  • Put your Hydro Flask on the stove, campfire, or any external heat source to heat it up. Due to the double wall vacuum insulating property of the flask, outside temperature will not change the inside beverage temperature. If you put your flask on any sort of stove or heat source, the heat will damage the outside of the flask.


  • Wash your flask with a bottle brush. You can find a perfect bottle brush in the baby section of most grocery stores. Use the bottle brush as frequently as possible.
  • Use white distilled vinegar for cleaning. You can use household white distilled vinegar to help remove any stains or discoloration on the inside of your flask. We recommend putting ½ cup of vinegar in your flask, gently swirling the vinegar around to wash any affected areas and let sit for 5 minutes. Rinse thoroughly with warm water and repeat if necessary.
  • Use baking soda for cleaning your Hydro Flask. For those stubborn spots inside your Hydro Flask, mix 2-3 tablespoons of baking soda with a small amount of warm water to form a scrubbing paste. Dip the bristles of your bottle brush in the paste and work paste into affected area on the inside of your flask. Repeat as necessary until stain disappears.
  • Wash your caps in the dishwasher. All Hydro Flask caps are top-rack dishwasher safe. The cap may last longer if it is hand washed, but if it needs to be deep cleaned, the dishwasher is acceptable.

Manufacturer: Hydro Flask

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