Standard Mouth Flat Cap

Standard Mouth Flat Cap Black

Standard Mouth Flat Cap


Availability: Out of stock

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Ice cold steel.

Some people never want their liquids to be in contact with plastic, so we created this bottle cap. With a durable polypropylene PP#5 top and inner threading made from 18/8 stainless steel, you’re assured the purest drinking experience every time you take a sip.

Works with any of our Standard Mouth bottles.

  • Patent-pending, leak-proof design
  • Durable polypropylene PP#5 top
  • 18/8 stainless steel inner threading
  • BPA-free and toxin-free
  • Compatible with all standard mouth bottles
  • Lifetime Warranty
Standard Mouth Flat Cap is rated 3.0 out of 5 by 2.
Rated 1 out of 5 by from Breaks easily I had two of these caps and both broke easily. The first one broke after several months of use and the second one broke just today (again after several months of use). Both caps broke in the exact same way. When I opened my bottle, the plastic top plastic part cracked and it separated from the rest of the cap. I did not drop it or anything. I don't know if its the type of plastic used or if it's the design but this cap breaks seemingly by itself.
Date published: 2015-10-06
Rated 5 out of 5 by from Love this lid. Water tastes crisp and fresh all day due to this lid keeping the water from coming into contact with any plastics. I wish it wouldn't break so easily when droppedbbut otherwise a great product.
Date published: 2015-10-26
  • 2016-05-03T08:27CST
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Q & A

By mistake the plastic seal wasn't in the cap, Hydroflask bottle lying on it's side on the car seat, what a mess! The lid was sealed tightly but without the seal in place liquid leaked out of the Hydroflask. I won't make this mistake again!

Asked by: Aneeda
Check out our warranty page:
Answered by: Hydro Flask Customer Team
Date published: 2015-11-25

Does this cap fit the narrow mouth bottles?

Asked by: captainsabre
The Standard Mouth Flat Cap fits only the Standard Mouth Hydro Flasks.
Answered by: Hydro Flask Customer Team
Date published: 2016-02-25

Will this cap fit the 32oz hydro flask?

Asked by: NathanAlan
Only our Wide Mouth caps will fit the 32 oz Hydro Flask. The Standard Mouth Flat Cap is designed to fit our Standard Mouth bottles.
Answered by: Hydro Flask Customer Team
Date published: 2015-12-02

Will stainless steel caps ever be available for ALL styles? I have narrow mouth and wide mouth hydro bottles for which I would like stainless steel caps but I only see standard mouth stainless steel caps available. I would very much like to ditch plastic!

Asked by: bosatsu
Not at this time, but thank you for your feedback. We appreciate it!
Answered by: Hydro Flask Help
Date published: 2016-04-11

what are the metals that are in a hydro flask

Asked by: shane
18/8 Stainless Steel.
Answered by: Hydro Flask
Date published: 2015-09-27

Does the flat cap fit the 18oz "coffee and tea" hydro flask ? 

Asked by: John29
No, the coffee and tea Hydro Flask has a wide mouth. The flat stainless cap fits standard mouth flasks.
Answered by: Mcroup
Date published: 2015-07-17

will there be a stainless flat cap available for the 40 oz hydro flask?

Asked by: sharonchun
We do not currently have this type of cap, you never know what you will see from Hydro Flask down the line. Will pass on your feedback to our product team!
Answered by: Hydro Flask Customer Care
Date published: 2016-03-19

What is the inside dimension of the standard mouth flat cap?

Asked by: AndrewO406
  • 2016-05-03T08:01CST
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