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Hydro Flask Stainless Steel Flat Cap - Standard Mouth

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The Stainless Steel Flat Cap is perfect for those who prefer their liquids never touch any plastic. The top is made from polypropylene PP#5, while the inner threading is made from 18/8 stainless steel, which ensures an all stainless steel contact with the flask's contents. 

The Flat Cap fits on our Standard Mouth flasks, including the 12 oz and 21 oz flasks.

Like all Hydro Flask products, the Stainless Steel Flat Cap is both BPA and toxin free.

Posted by Denita on 04/10/2015

5 Star Rating

LOVE my HydroFlask

I bought my first HyrdoFlask in 2010 and have purchased many many more since! I just returned my beloved Growler after 5 years of keeping my water COLD in the HOT HOT South Florida weather. Warranty replacement was easy, I now have my new Growler. I only wish HyrdoFlask would offer more colors in the 64 oz size.

Posted by Anthony C on 04/09/2015

5 Star Rating

16 oz True Pint for Coffee too!

Picked up a True Pint to add to my Hydroflask family of 5 water bottles. Not for beer but for coffee. And it is just as amazing as the bottles. Now I just need a lid and it would be perfect.

Posted by Tamandal1205 on 04/09/2015

5 Star Rating

The Best!

I recently switched from a competitor's plastic bottle and absolutely LOVE the double-wall insulating properties of the Hydro Flask. The 32oz holds just enough ice water that I can survive the HOT Florida days. I can't wait to take mine camping... Wish I discovered Hydro Flask sooner!

Posted by Katie Brunson on 04/06/2015

5 Star Rating


I seriously wish I could give 100+ stars on this bottle. When I say AMAZING I mean it. DOES NOT LEAK. DOES NOT SWEAT. (we all can say we hate when we have a sweating bottle) I'm seriously in love and have been telling everyone about it. I left it at a friends the other night and I was so upset I left it. I highly recommend getting one. Will be ordering the straw part next!

Posted by Brooke on 04/02/2015

5 Star Rating


What an awesome water bottle! I bought one from my hot yoga studio in hopes of keeping my water cold during the class-- it totally works! I found my self using it ALL the time! I'm a college student and usually carry a water bottle around all the time anyway-- I'll put ice cold water (with half a tray of ice cubes) in it one morning and a night night the ice cubes are still whole and the water is freezing! Only buying this brand of water bottle from now on-- I love it!

Posted by Anne Marie on 04/01/2015

5 Star Rating


I got a brand new one free since the previous one had some odd rust in the bottom... CRAZY AMAZING!

Posted by Thompsie S. on 04/01/2015

5 Star Rating

Out with my Nalgene....IN WITH MY HYDRO FLASK!

I drink approximately 100 oz. of water per day (due to a medical condition). I used to use Nalgene and Camelbak bottles exclusively to carry my water to the office, the gym, etc., but I decided to try the Hydro - it caught my eye at R.E.I. on a display! I had always wanted a sleeker looking bottle that could hold more than 32 oz. but I could never find one! I own the 40 oz. Hydro Flask in blue and now I cannot wait to get a smaller pink one as well! Here is what I adore about the Hydro Flask: DOES NOT LEAK! DOES NOT SWEAT! Sleek design! Thanks so much to the designer of these bottles!!!!

Posted by Kelly E on 03/28/2015

5 Star Rating

The best water bottle ever!

I purchased my hydro flask 3 years ago and fell in love with it the very first day. It goes everywhere with me. I live in Florida and my hydro flask keeps my water ice cold, even on the beach. When I was on a cruise I used my hydro flask to keep my mudslides frosty. It is by far the best water bottle you will ever purchase.

Posted by Joy on 03/28/2015

5 Star Rating

best water bottle ever

I love this water bottle - actually I have two. People thought I was crazy the way I went on and on about the great features of this bottle. Put it in your backpack; doesn't sweat on papers/books/electronics in your backpack. I frequently work outside in remote locations where you have to carry your water with you; after slogging through rough terrain it is so nice to get cold water from my Hydro Flasks instead of the tepid water from previous water bottles I have used. For Christmas last year, I purchased 21 oz Hydro Flask bottles for my entire family. They did kind of look at me strangely when first opening the gift, but since they had the opportunity to use them, the family is telling me how much they use their Hydro Flask bottle and think the bottles are GREAT!

Posted by William C. Herington Jr. on 03/25/2015

5 Star Rating

PERFECT Enough said !!!

If you don't own at least one you should ask yourself WHY NOT. Have gotten several from Dutch Bros. coffee and couldn't ask for anything better. Two great businesses from the state of Oregon.

Posted by Adrienne Woodward on 03/23/2015

5 Star Rating

Awesome product and great customer service to boot!!

I love, love, LOVE this water bottle!! I am a constant iced tea drinker, and the 64oz holds all the tea and ice I need for a 12-hour shift! Did I mention it also keeps the ice solid and my tea ice-cold for the entirety of my shift also?? Excellent! I have a habit of carrying my full jug by the handle, and after about of year of heavy use, the plastic strap that connects the cap to the bottle gave in and broke. I filled out the customer complaint form offering to purchase a new lid, and they shipped a new one to me the next day, free of charge! Not even a few for the shipping! I can't praise this product or company enough... Expensive, but worth every penny! Thank you!

Posted by Mercer on 03/18/2015

5 Star Rating

Best Water Bottle I've Found!

I am always carrying a water bottle. I used to use Nalgene and glass water bottles. I loved the size of the Nalgenes and the cleanliness of glass. This bottle provides the perfect combination of both. It is large enough to avoid having to refill constantly and it does not retain any tastes/smells as plastic does. This water bottle also keeps my water ice cold for several hours. Living in Arizona, water bottles usually heat up fairly quickly which leaves the water undrinkable. I left this water bottle in my car for hours and the water was still cold! Highly recommend!!

Posted by Scott on 03/18/2015

5 Star Rating


I bought myself one of these about a year ago as a birthday gift to myself. I have used it every day since for my morning coffee, and I have absolutely no complaints! I love it so much that I now have a water bottle and a true point on my radar to purchase in the very near future. Hands down the best travel mug I have ever owned!

Posted by Doug on 03/15/2015

5 Star Rating

Great Upgrade

I had been using another rugged water bottle for years and liked it fine but hated the water rings left behind wherever I set it down. After doing more research than I ever thought I would do for a water bottle, I purchased the Hydroflask. Rugged and solid construction with a nice finish. I was a little concerned about not having any splash guard, but to my surprise the shape of the bottle has a way of keeping ice at bay. Great bottle, absolutely recommend!

Posted by Andrew on 03/10/2015

5 Star Rating

Keepin' it Frosty

When your Dale's Pale Ale's gone stale, it's a bummer. These new pints from Hydroflask will make sure your brew stays as cool as your toes in a mountain river. I have some steel pints from other brands and I love the Hydroflasks way better. They don't get cold or hot to the touch when you fill them, and they do not sweat like others, while they keep your beer frosty for the whole 16 oz., even in the dog days of summer. I wish they had some more colors, and it'd be nice to see Hydroflask come out with an accessory lid. I love how they designed an inside lip at the bottom so you can stack these guys without them getting stuck on each other.

Posted by Bubba Jones on 03/09/2015

5 Star Rating


love it

Posted by Eric on 03/05/2015

5 Star Rating

Best drinking container ever

I've never had a drinking container that keeps cold drinks so cold for so long. No longer do I need to bring a cooler or freeze my drinks prior to heading to the beach! Lives up to it's claim. I've also never had a bottle that feels so solid, the caps do not leak at all, even the straw cap, and taking it to the pool it even floats when full of liquid!

Posted by Justin Shaver on 03/05/2015

5 Star Rating

A true beliver

I purchased my new Hydro Flask after hearing a co-worker rave about the two he has. I have had it over a week now and I can say that I'm a true believer. I filled it with ice at 0530 used it throughout the day till 1800 that night. To my amazement there was still ice in the flask. I have been made a believer in this product and will be purchasing a 12oz to use as my morning coffee container. Thank you for the wonderful products you make and I look forward to purchasing some as gift this year.

Posted by Lys on 03/05/2015

5 Star Rating

Use it every day.

I can't say enough great things about the Hydro Flask bottle and tell all my friends to buy one of their own. My coffee/tea stays a steady hot temperature throughout the workday. I can keep iced drinks cold for even longer, and the ice cubes survive so much longer than in other bottles. Perfect for a long bike ride or cold winter days.

Posted by Alyssa on 03/01/2015

5 Star Rating

Obsession with hydroflask.

My roommate and I collectively own 7 of these bottles. They are perfect for every occasion and work flawlessly. Our only complaint is that the liquids inside are too hot or too cold, which mean the product is exceeding at its job!

Posted by Hawaii on 03/01/2015

5 Star Rating


I got a hydro flask in recent months I can honestly say there is nothing like it. I go to school that is far from where I live so when I walk I need some refreshing water. So I decided to get myself a hydro flask. Best choice I have ever made. Why did I wait so long

Posted by Monroe Charles on 02/26/2015

5 Star Rating

Christmas Year Round

Got one of these for Christmas & it's like winter year round! I live in Hawaii, so warm to hot water is very normal if you leave your bottle in the car or even just sitting on a desk near a window. I was using a rival product & it was good, but the Hydro Flask is better! It's also a bit more manageable in size than my previous bottle. All up, definitely a fan for life. I use it every day now! Plus, Bend company! <3 Oregon.

Posted by Rob on 02/26/2015

5 Star Rating

Awesome Flask, excellent customer service

I bought this flask about 8 months ago and use it daily for work, among other things, always water. Keeps water cold all day with no problem. The best part? Although the cap ring broke, I submitted the warranty form and within minutes I received a notification that my replacement was being processed... awesome!

Posted by Kim Wolf on 02/25/2015

5 Star Rating

Homemaker, Health & Beauty Buyer at Healthy Alternative

I was given my wonderful large Hydro Flask from a rep at couple months ago & I have used it everyday since. I make a pot of my own tea blend every morning, fill my flask & refill my thermos that I keep out on the sales floor, all day long. EVERY TIME I re-open the flask for a refill, my tea is STILL piping hot. I absolutely LOVE it & I'm trying to get our owner to carry them in the store.

Posted by Ed on 02/24/2015

5 Star Rating


This is by far the best thermos I've owned. I have pretty much every model they've designed. My go to 40oz that I bought nearly three years ago is still going strong after numerous drops on the cement and trail and shows tons of character. Customer service is incredible. I've had to use them several times for replacement caps caused by my own carelessness and they have never given me any grief about sending a replacement.

Posted by Meggie on 02/23/2015

5 Star Rating

No problems lid is great.

I haven't had any problems with a leaky lid, have dropped my water bottle at least 5 times and it has survived. I totally recommend!

Posted by Diana Correia on 02/18/2015

5 Star Rating

I found the perfect water bottle!

I have been on the quest for a long time,in search for a water bottle that fits my lifestyle. I'm always on the go & when I leave the bottle inside a hot car for a long time it keeps the water/juice cold. I love it. It also does the same for hot coffee. We had many blizzards this year. When there was a threat of a power outage, I would brew my coffee,pour it in the growler and it was still warm the following morning. It was just awesome. Especially when theres no electricity due to these power outages. I used it so much I broke the cap at one point. Just the pice of plastic that attaches it to the growler. As promised, the life time warranty does work. I got my part in the mail with no hassles. Thank you!

Posted by Gina on 02/15/2015

5 Star Rating

Please give us other lids for this??

I really want this bottle but hesitate due to the narrow mouth opening and lack of lid choices. I have the wide mouth 18 oz and love it!! I would like this one because it holds more but please make it wide mouth so that my straw lid fits or make other lid options for this. Please, please!!

Posted by Jeremy on 02/14/2015

5 Star Rating

Best Bottle Ever

I live in the tropics of North Queensland Australia. I've had the 32oz wide-mouth for 2 months (during the peak of a hot and humid summer) and it is definitely the best water bottle I've ever had. Keeps cold a long time and doesn't sweat! The straw lid (which I use without the straw) makes it perfect!

Posted by Ben Jenkins on 02/12/2015

5 Star Rating

Best Bottle Around

I have tried hundreds of bottles and hydroflasks are the best around hands down. I work at a sporting goods store and we recently started stocking them. First I got the 32oz water bottle and I absolutely loved it. I couldn't believe how long the ice would last in the bottle. I like to stay hydrated and having to fill up the bottle 5+ times a day with water was beginning to be a hassle so I went ahead and got the growler. Yes this bottle is expensive but well worth the money. I found that with the growler it would keep the ice in there for even longer. I tested the 64oz growler by filling it to the brim with ice and water and let it sit capped on my blacktop driveway in 93+ degree weather too see how long the ice would stay frozen. Mind you this is the black growler as well. After 24 hours the ice had barely melted! After 72 hours there was still about the equivelant to a cube floating around in there. I have been using these two for about 3 months now and have found that they are large and heavy they are still the best bottle around. I recently also bought the 18oz wide mouth for hot tea and coffee this one is not near as good for cold items but perfect for keeping your coffee hot well through lunch. 18oz for hot beverages. 32oz for soda, juice, tea, mixed drinks or whatever, and 64oz for ice cold water for days. The perfect combo. Hydro4lyfe.