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Standard Mouth
Standard Mouth Flex Cap
Standard Mouth Flex Cap is rated 4.4 out of 5 by 108.
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Regular Price $9.95
$7.46
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Standard Mouth

Standard Mouth Flex Cap

Standard Mouth Flex Cap is rated 4.4 out of 5 by 108.
  • y_2020, m_7, d_14, h_15
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Regular Price $9.95
$7.46
Size Chart
Hydro Flask Pack Size Chart
Available Sizes S / M M / L
Torso
Measurement		 18 - 19 in 19 - 22 in
43 - 48 cm 48 - 56 cm
Hip
Measurement		 22 – 46 in 26 – 46 in
56 – 117 cm 66 – 117 cm

  1. 1. Torso Measurement

    • A. Bring your chin to your chest and feel for the most prominent bony bump where the slope of your shoulders meets the back of your neck. This is your C7 vertebra, and the top of your torso measurement.

    • B. On each side of your body, feel for the top of your hip bones, just below the sides of your ribs. With fingers pointing forward and thumbs pointing backward, draw an imaginary line between your thumbs. This is the bottom of your torso measurement.

    • C. Stand up straight and have a friend with flexible measuring tape measure the distance between your C7 vertebra and the imaginary line between your thumbs. That’s your torso measurement. If you are between pack sizes, go with the smaller size.

  2. 2. Hip Measurement

    While your torso measurement is the best indicator of your pack size, it’s still important to check your hip size when using a hipbelt. To find your hip measurement, wrap a flexible tape measure around the top of your hip bones, just below the sides of your ribs. This measurement is slightly higher than your waistline

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Standard Mouth Flex Cap
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Moves with you.

Strong yet flexible, our Standard Mouth Flex Cap is the perfect companion for spontaneous campouts, epic road trips, and everything in between. Made with stainless steel pivots and an easy-to-carry strap, this cap has Honeycomb Insulation™ to help keep your drinks cold for up to 24 hours or hot up to 12. Pair it with any of our Standard Mouth bottles.

Product Benefits

  • Compatible with all Standard Mouth bottles
  • Honeycomb Insulation™ helps keep cold drinks cold and hot drinks hot
  • Durable, stainless steel pivots allow the strap to move easily
  • BPA-Free and Phthalate-Free
  • Lifetime Warranty
Let's Go!

Today is wide open. You lead, we'll follow.

#HeyLetsGo

Hydro Flask supports non-profit organizations focused on building, maintaining, restoring, and providing better access to parks. Since 2017, we have been doing just that:

  • 92 Non-profits supported non-profits.
  • $1.5 million Dollars donated donated.
  • 26,043 Bottles donated bottles.
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Reviews
Rated 5 out of 5 by from Perfect fit! The replacement cap fits perfectly on the flask! Thank you!
Date published: 2020-06-23
Rated 5 out of 5 by from Keeps drinks cold I used this to hold cold drinks and it kept it cold for hours. I definitely recommend this product gor keeping beverage cold. I have not tried it with hots drinks though but I would assume it would keep drinks hot for a long period of time as well.
Date published: 2020-02-08
Rated 5 out of 5 by from great product I had brought this water bottle and like how it can make your drink hot or cold depending on what kind of drink you have that day . Also the packaging of the water bottle it's very sleek and nice love it .
Date published: 2019-11-27
Rated 5 out of 5 by from Great water bottle I like this water bottle my kids love it they use it everyday. I like how the water bottle keeps your drinks cold and also keeps the drinks warm. I highly recommend it I need to buy a bunch of them Is good for the kids to bring cold drinks to school or the gym
Date published: 2019-11-15
Rated 5 out of 5 by from Fit my need I needed a lid to match a cobalt hydroflask my family had an extra of. It came and fit perfectly. High quality stuff, will use until I lose it!
Date published: 2019-11-15
Rated 5 out of 5 by from Love love love I had the old original top and the handle hurt my hands, so I bought this one and love it. It's super secure and the handle is awesome!
Date published: 2019-11-06
Rated 5 out of 5 by from Stainless is terrific I've lived and traveled for six years with my stainless coffee 16oz hydro flask. Empty it goes through security and customs with no problem. Just got it a "boot" for protection. The black flip lid has lasted well. Alternative color lids are fun, too. I can't imagine my days without it.
Date published: 2019-10-29
Rated 5 out of 5 by from I love this! I love this lid!! To be honest I didn’t realize how much I would appreciate it either - I love that I can hook my finger through the lid and carry it around that way. So convenient!! Love love love - want for every bottle!
Date published: 2019-10-18
Rated 5 out of 5 by from Mouth flex cap This cap is just awesome!! If you don't have one please do yourself a favor and get one. It was easy to screw on and off; and the alignment of the was great. I never had to fumble with getting it off or on. I was impressed on how it kept my beverage hot/cold for hours. I really enjoyed the easy carring handle it provided. I have recommended this to all my friends and co-workers.
Date published: 2019-10-14
Rated 5 out of 5 by from Perfect form factor This is a perfect size, excellant grippabilty and really does keep ice for hours and hours and hours and a few more hours. This will be used daily and enjoyed for years. Ifnininly had a box full I could give to friends for christmas.
Date published: 2019-10-13
Rated 5 out of 5 by from Best water bottle on the market The Hydroflask has many imitators but is the best water bottle out there right now. It keeps liquids hot all morning and cold for what seems like days. There's no condensation on the outside or bottom of the bottle either when you fill it with ice. The lid is completely leak-proof and doesn't have annoying flaps, mechanisms or crevices that are super hard to clean.
Date published: 2019-10-11
Rated 5 out of 5 by from Super strong and durable! The cap withstands amazingly! I usually take my bottles to the gym and toss and swing them around everywhere and it has not even budged to wear down at all! Keeps my drinks cold and secure! I wouldn’t go with any other brand, it definitely holds up to my standards.
Date published: 2019-10-09
Rated 5 out of 5 by from Greatest Water Bottle Ever! I am very pleased with this Hydro Flask! The size is prefect to keep in my everyday bag, and it keeps my drink cool/hot for hours. The color doesn't fade after many washes which is a plus. It is also durable and I love the color! I am definitely happy with it.
Date published: 2019-10-08
Rated 5 out of 5 by from Smart and simple The flex cap is great - it’s not a stiff loop like some, so it’s comfortable to carry. Long enough to be usable but not to dangle, which is good. Feel is great and it insulates really well - very little loss of temp at the neck.
Date published: 2019-10-08
Rated 5 out of 5 by from Hydro Flask Standard Mouth Flex Cap This cap has been in use for over a month now. Its been through workouts, bike riding and just back and forth to work. The cap has held up well through all of these activities. Stays in shape through dishwashing and drying but I think it may be better to hand wash. Given my activities, I think i would prefer the cap with mouth piece so I don't have to unscrew the cap every time, just my preference. Construction appears good so far so no issues. Price is not to bad so I may just have to purchase one extra
Date published: 2019-10-07
Rated 5 out of 5 by from Love Hydro Flask Just like my other Hydro Flasks, I love this water bottle equally. I have used this one for both hot and cold liquids and love it. I am amazed at how I can put ice in it in the am and add water throughout the day and there is still ice in it to keep my new water cold. I don't think there will ever be a reason to use any other water bottle than a hydro flask and this one with a standard mouth cap is probably my new favorite!
Date published: 2019-10-07
Rated 5 out of 5 by from Leak Proof Cap The standard mouth flex cap for the Hydroflask fits perfectly and tightly. The standard mouth flex cap doesn't leak and keeps drinks cold/hot and secure while traveling, exercising, or to use as a spill proof container at work.
Date published: 2019-10-06
Rated 5 out of 5 by from I love this product I love how this product keeps cold drinks cold and hot drinks hot for hours especially cause I’m a bus driver and work long hours it really helps, I even told my brother about it and now he want one...thanks again.
Date published: 2019-10-06
Rated 5 out of 5 by from Great product I really like these insulated water bottles. They keep my water and ice cold for hours. The flex caps are easy to use. The hydro flask is light to carry when walking and not bulky. I also like that the cap has a loop that makes it easy to carry.
Date published: 2019-10-06
Rated 5 out of 5 by from Fits 21oz Hydro Flask Bottle perfectly If you need a replacement lid for your Hydro Flask this fits the 21oz perfectly. No leakage at all. Also fits my 24 oz bottle. Made well and will last as long as I don't lose the bottle. I like the top loop for carrying and strapping to my backpack. I hand wash but could toss in dishwasher basket if you have one.
Date published: 2019-10-06
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Questions

Will this top fit the 25 oz wine bottle flask?

Asked by: Lsherm
Yes, our standard mouth caps will fit on the wine bottle.
Answered by: Consumer Service
Date published: 2020-04-10

Will this one fit on the 12oz kids one? I have ordered one for her and she keeps coming home from school and it leaks all over her backpack.

Asked by: izzybizzie200
The standard mouth caps will only fit the standard mouth bottles. Please contact customer service at 888-584-9376 to discuss this further.
Answered by: Consumer Service
Date published: 2019-10-29

Will this fit an 18oz hydro flask? If not, is there a lid for an 18oz like this?

Asked by: hopefulhydroflask
This cap will fit the 18oz standard mouth flask.
Answered by: Consumer Service
Date published: 2019-10-28

I lost my old cap from the bottle bought back in 2015. Does this fit the old 21 oz standard bottles?

Asked by: bkelly808
It should, yes. If you purchase one and it does not fit, please contact customer service at 888-594-9376.
Answered by: Consumer Service
Date published: 2019-10-27

Will this cap fit 25 oz Wine Bottle?

Asked by: Sue95
Yes, the Standard Mouth Flex Cap will fit the 25oz Wine Bottles.
Answered by: Consumer Service
Date published: 2019-06-13

Our 21 oz, insulated flasks are our favs but over time, water got into the caps and the standard rubber ring developed mold.  Took it apart & cleaned it, but the seal is discolored & water is difficult to remove from cap.  Will new design solve this? 

Asked by: Nancy39
We'd be happy to replace your cap for you under our Lifetime Warranty. You can fill out a warranty claim here: (http://www.hydroflask.com/warranty/)
Answered by: customer servcie
Date published: 2018-05-01

Does the standard mouth flex cap come in white?

Asked by: spyro22
The white standard mouth flex cap can only be purchased through the MyHydro website. You would have to customize the flask to get the white cap.
Answered by: customer servcie
Date published: 2018-03-28

Is this lid leak proof?

Asked by: JordanK
The flex cap is more of the leak proof option because it has no openings in the caps.
Answered by: Hydro Flask Customer Team
Date published: 2018-07-08
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Hydro Flask supports non-profit organizations focused on building, maintaining, restoring, and providing better access to parks. Since 2017, we have been doing just that:

  • 92 Non-profits supported non-profits.
  • $1.5 million Dollars donated donated.
  • 26,043 Bottles donated bottles.