Hiking and Wide-Mouth Flasks

Wide mouth

Three listings at 32 and 40 oz. Wide mouth is the one that takes standard ice cubes and lets a brush reach the bottom.

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  Most lids stated in this category

  Three lids in the box. Every other flask listing here states one lid, so three appears exactly once.

  IRON FLASK Wide Mouth with 3 Lids, 32 oz

  32 oz statedListed here at position 01

  The listing states three leakproof lids, BPA-free, cold 24 hours, sweat free.

  A 32 oz wide mouth flask that ships with three lids, which is the whole reason a wide mouth thread is worth having. The listing states leakproof lids, BPA-free construction, cold for 24 hours and a sweat free exterior; the 24-hour figure names no conditions.

  What the listing gives you

  • Three lids in the box means the drinking method can change without another purchase
  • Wide mouth takes ice cubes rather than only crushed ice
  • Stated 32 oz volume with a single size on the listing
  • Listing states leakproof lids rather than only spill resistance

  What it leaves open

  • "Cold 24 hours" is stated with no starting or ambient temperature
  • Three lids means three gasket sets to keep clean and dry
  • A wide mouth is harder to drink from while moving than a straw

  Suits One flask body that has to serve as a straw bottle, a chug bottle and a lidded cup.

  View the listing on Amazon
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  Hydro Flask Wide Mouth Flex Lid, 32 oz

  32 oz statedListed here at position 02

  The listing states insulated stainless steel, non-spill, leakproof, refillable.

  A 32 oz wide mouth flask with a flex strap lid, stated as non-spill and leakproof. The wide opening is the functional part: it takes ice and it takes a bottle brush, which is more than most straw lids allow.

  What the listing gives you

  • Wide opening takes standard ice cubes and a cleaning brush
  • Listing states both non-spill and leakproof
  • Flex strap doubles as a carry point
  • Insulated stainless steel construction per the listing

  What it leaves open

  • The listing states no retention figure at all
  • A wide mouth pours faster than expected when tipped in a car
  • One lid in the box, so a straw is a separate purchase

  Suits A daily flask that gets filled with ice and washed with a brush.

  View the listing on Amazon
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  IRON FLASK Wide Mouth with Straw, 40 oz

  40 oz statedListed here at position 03

  The listing states a leakproof straw lid, BPA-free, cold 24 hours, sweat free.

  The 40 oz wide mouth body with a straw lid rather than a lid set. Straw plus wide mouth is a good combination for a desk and a poor one for a bag that gets laid flat, whatever the leakproof wording says.

  What the listing gives you

  • Wide mouth for ice with a straw for drinking, in one configuration
  • Stated 40 oz volume, a full step up from the 32 oz bodies here
  • Listing states a leakproof straw lid
  • Listing states BPA-free construction

  What it leaves open

  • "Cold 24 hours" and "sweat free" are stated without conditions
  • A 40 oz flask full of ice water is heavy to hold one-handed
  • One lid only, unlike the three-lid listing in the same family

  Suits A large desk flask where refilling should happen once a day, not four times.

  View the listing on Amazon

Jugs

One listing at 64 oz with a handle. Above about 40 oz the handle stops being a convenience and starts being the reason it is usable.

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  Largest stated capacity in this category

  64 oz, and 64 oz appears exactly once across the seven flask listings here.

  STANLEY IceFlow Flip Straw Jug, 64 oz

  64 oz statedListed here at position 04

  The listing states a carry handle, twist-on lid with flip-up straw, leakproof, BPA-free.

  A half-gallon jug with a handle and a flip-up straw in a twist-on lid. The handle is the design decision that matters at this volume, because 64 oz of water is roughly four pounds before the jug itself.

  What the listing gives you

  • Carry handle is stated, which no other flask listing here mentions
  • Flip straw folds down flat against the lid
  • Largest stated volume among the flasks here
  • Listing states a leakproof lid

  What it leaves open

  • Full weight makes this awkward to drink from without setting it down
  • A flip straw has a hinge and a gasket that both need drying
  • No insulation retention figure is stated

  Suits A jug that lives on a desk or in a car footwell and gets refilled once.

  View the listing on Amazon

Narrow mouth

Three listings from 6.7 to 24 oz. Narrower bodies fit pockets a wide mouth does not, at the cost of ice and cleaning access.

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  Hydro Flask Standard Flex, 21 oz

  21 oz statedListed here at position 05

  The listing states insulated stainless steel, non-spill and leakproof.

  A 21 oz narrow mouth flask stated as non-spill and leakproof. Narrow mouth means a slower pour and a smaller opening for ice, in exchange for a body that fits more places.

  What the listing gives you

  • Narrow body fits a side pocket that a wide mouth does not
  • Listing states both non-spill and leakproof
  • Slower pour is easier to control while walking
  • Insulated stainless steel construction per the listing

  What it leaves open

  • Narrow mouth takes crushed ice more easily than cubes
  • Harder to reach inside with a brush than a wide mouth
  • No retention figure is stated

  Suits A pack side pocket where a wide flask will not sit.

  View the listing on Amazon
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  IRON FLASK Narrow Mouth with Straw, 24 oz

  24 oz statedListed here at position 06

  The listing states a leakproof straw lid, BPA-free, cold 24 hours, sweat free.

  A 24 oz narrow mouth flask with a straw lid. The narrow thread limits which replacement lids fit, which is the trade for a slimmer body, and the listing repeats the same cold-for-24-hours claim used across this family.

  What the listing gives you

  • Slim body for a bottle pocket, with a straw for drinking
  • Stated 24 oz volume
  • Listing states a leakproof straw lid
  • Listing states BPA-free construction

  What it leaves open

  • Narrow thread narrows the choice of swap lids
  • "Cold 24 hours" is stated without conditions
  • Straw and gasket need taking apart to dry

  Suits A slim straw bottle where a wide mouth is too fat for the pocket.

  View the listing on Amazon
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  Smallest stated capacity in this category

  6.7 oz, and 6.7 oz appears exactly once across the seven flask listings here.

  Hydro Flask Micro Bottle, 6.7 oz

  6.7 oz statedListed here at position 07

  The listing states a leak-proof pocket or purse flask, insulated.

  At 6.7 oz this is the smallest vessel in the catalog and the one that defines the left edge of the capacity plot on the front page. The listing calls it a pocket or purse flask and states a leak-proof design.

  What the listing gives you

  • Small enough for a coat pocket, which nothing else here manages
  • Listing states a leak-proof design
  • Insulated construction per the listing
  • Sets the low end of the stated size range on this site

  What it leaves open

  • 6.7 oz is a few mouthfuls, so it is a top-up rather than a supply
  • Small openings are the hardest to dry properly
  • No retention figure is stated

  Suits A pocket where any full-size bottle is out of the question.

  View the listing on Amazon

Questions this category actually raises

Related reading

• Capacity and cup holders
• Insulation claims
• Cleaning straws and gaskets