Hydro Flask Standard Mouth Water Bottle with Flex Cap Black 21oz/621ml
Hydro Flask Standard Mouth Water Bottle with Flex Cap Black 21oz/621ml
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HYDRO FLASK

Hydro Flask Standard Mouth Water Bottle with Flex Cap Black 21oz/621ml

4.4 stars out of 29 reviews
(4.4)|
29 ratings
Hydro Flask Standard Mouth Water Bottle with Flex Cap Black 21oz/621mlHydro Flask Standard Mouth Water Bottle with Flex Cap Black 21oz 621mlHydro Flask 21 oz Standard Mouth w Standard Flex Cap White
Actual Color:Black-Out of stock
selected, Black, $32.95, Out of stock
$32.95/ea
White, $30.95, Out of stock
$30.95/ea

Key item features

  • Temperature Retention: TempShield double-wall vacuum insulation keeps drinks cold up to 24 hours, hot up to 12.
  • Leakproof Cap: Flex Cap is leakproof when closed, ensuring no spills.
  • Insulated Cap: Honeycomb Insulated Cap for maximum temperature retention.
  • Durable Material: Made with 18/8 pro-grade stainless steel for durability, pure taste, and no flavor transfer.
  • Colorful Coating: Color Last powder coat is durable, sweat-free, and colorful.
  • Safe and Convenient: BPA-Free and dishwasher safe for easy cleaning.
  • Versatile Use: Not for use on a stove, in a microwave, or freezer; fits in cup holders and packs.
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Current price is $32.95$32.95/ea
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4.4 out of 5 stars
stars29 ratings16 reviews
How item rating is calculated
  1. 5 stars72% (21)
  2. 4 stars14% (4)
  3. 3 stars3% (1)
  4. 2 stars0% (0)
  5. 1 star10% (3)

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Showing 1-3 of 16 reviews

Jul 20, 2025
anonymous
Item details
Color: Black
Sold bySyco DealsDelivered byWalmart
5 out of 5 stars review

Verified Purchase

I recently got the HydroFlask Standard Math Water Ball, and it's honestly one of the best bottles I've owned. Right out of the box, the design stood out — the math-themed graphics are fun, smart, and a great conversation starter. The build quality feels premium, with a solid stainless steel body and a powder-coated finish that resists scratches and sweat. I've been using it daily, and it keeps my water cold for over 12 hours easily, even when I'm out in the sun. The leak-proof lid gives me peace of mind when tossing it into my bag, and the wide mouth makes it super easy to clean or add ice. I also love how easy it is to grip, and the size fits well in my backpack's side pocket. The only downside is that it's a bit bulky for smaller car cup holders, but that's a small trade-off for how well it performs. Overall, I'd definitely recommend this to students, gym-goers, or anyone who wants a unique and reliable water bottle with some personality.

Incentivized Review
Helpful?5TBOCOLBTR38838120600
Jul 30, 2025
anonymous
Item details
Color: White
Sold bySave On PrimeDelivered byWalmart
5 out of 5 stars review

Verified Purchase

Cold All Day, Built to Go

I've been using the Hydro Flask 21 oz Standard Mouth, and it's been great for keeping my drinks ice-cold all day—ice usually lasts until the evening. I like that it never sweats, so I can toss it in my bag without worry. The Flex Cap is easy to twist on and off, though I'm not a huge fan of the exposed mouthpiece. It fits perfectly in my car's cup holder and side pocket of my backpack. It's tough, but I did get a small dent after dropping it—still works perfectly though.

Incentivized Review
Helpful?5TBOCOLBTR38838120600
Nov 20, 2025
Skyler
Item details
Color: White
Sold and shipped bySyco Deals
5 out of 5 stars review

Verified Purchase

great midsized bottle

good size for cup holders, not too heavy when full, great handle for carrying

Incentivized Review
Helpful?5TBOCOLBTR38838120600