This cap fits a standard 21 ounce flask and is the perfect go-anywhere companion. Read more >
Hydration on the Go. Our 21 oz. flask is the perfect go-anywhere companion on your busiest days. It stashes easily in a small shoulder bag, your pack’s side pocket, or your car cup holder, and holds enough to keep you going for hours without weighing you down. Now with our new Flex Cap for ultimate portablity.
Shipping & Returns
|Shipping Method||Rate||Expected Delivery Time|
|Ground||$6.00||3-7 Business Days|
|2-Day Air||$12.00||2-3 Business Days|
|Overnight||$19.00||1-2 Business Days|
|FREE Standard Shipping||Available for Greater Rewards members. Learn more >|
Returns are accepted within 60 days of the purchase date online. Your apparel must be in original and unworn condition, with tags still attached. Footwear returns must also include the original box.
Still Have Questions
See our Customer Service section for more details.
Hydro Flask Standard Mouth 21oz Flex Cap is rated out of 5 by 6.
Rated 5 out of 5 by staylor from Works great! The Hydro Flask brand is excellent and this works great!
Date published: 2018-10-04
Rated 5 out of 5 by Domer from Hydro flask I absolutely love my hydro flask! I use it for my workouts and hiking and the water stays cold just the way I like it!
Date published: 2018-09-16
Rated 5 out of 5 by Matt6329 from perfect! keeps cold. loop on lip is on solid.
Date published: 2018-08-10
Rated 5 out of 5 by SleepSkateSnow from Best container I've owned! Great quality, airtight seal, classy look. I won't ever use a different flask in the future.
Date published: 2017-10-26
Rated 5 out of 5 by Bear65 from Ice cold water for days! I like these bottles so much my entire family now has them. I carry them while hiking in the summer and I still have ice the next day and cold water 2 days later!
Date published: 2017-09-28
Rated 5 out of 5 by Lunayto from Great for keeping water cold! Works really well at keeping my water cold for an extended period of time.
Date published: 2017-09-15
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