Hydro Flask Vacuum Insulated Stainless Steel Water Bottle, Standard Mouth w/Loop Cap

I own a couple of Hydro Flasks, and the 21oz standard mouth is my favorite. For me, it strikes the right balance between portability and beverage capacity. I like to take it out golfing, hiking, to the beach, around the house, and everywhere in between. It fits in almost all cupholders (even the tiny ones in BMWs) and packs well in a backpack. The insulation is amazing and lasts, realistically, ~20 hours for cold beverages and ~8 for hot. Using larger ice cubes will extend the cold time, since larger cubes will mean less of the ice's surface area is exposed so they'll melt more slowly. The standard mouth allows you to use good sized cubes, whereas the narrow mouth will not. I chose mine in arctic white, which is nice, but it does get scuffed despite the very durable coating. A darker color will hide blemishes more effectively, but I like my bottle to have some character anyway.If you're an active person I'd recommend this bottle over other sizes since it travels better than the various wide mouth bottles. The standard mouth is too narrow in my opinion. If you're looking for a bottle to keep at your desk or around the house, I'd steer you towards the higher capacity wide mouth bottles with a flip-top straw lid. With those it's easier to take a casual sip, and you won't need to refill them as often. All in all I'd recommend Hydro Flasks to anyone looking for an insulated water bottle. They're high quality, durable, and come with a great lifetime warranty for peace of mind.**Update on 8/31/15**My 21oz standard mouth HydroFlask's vacuum seal has been compromised after ~6 months of ownership. Of the three HydroFlasks I have ordered from Amazon (2x 18oz wide mouth and 1x 21oz standard mouth), two have had defective vacuum seals--a failure rate of 66%. Maybe I've just been unlucky, but this is an unacceptably high failure rate. I'm currently submitting a warranty claim and will post updates as appropriate.**Update on 9/19/15**I was able to ship my HydroFlask back for replacement via USPS ground for ~$4. The order has been processed and my new flask is in transit. Expected arrival date is about a week from now. All in all it will have taken about a month to get my flask replaced, if everything goes smoothly. I'm glad that HydroFlask has a warranty system, but it's very slow. Hopefully this new flask will last for a long while.

Filled it with ice around 8 am, threw it in my backpack and took it out exploring with us in Nevada (Red Rock Canyon, Hoover Dam, the desert), forgot about it and went back to the hotel. The next morning I went to change the ice and to my surprise the ice from the previous day was entirely intact. It had not noticeably melted. This was during 100 degree weather sitting in the car in my backpack. It works.One thing I did alter, however, was to add a silicone sleeve over the powder finish of the water bottle. I took a sleeve from one of my glass Takeya bottles and worked it on over this one. It took some doing, as they aren't exactly the same size, but once I got it on it looks like it was designed to be there. You can find silicone sleeves here on Amazon - the slightly smaller ones than this bottle will fit, you'll just have to stretch it.I'm not sure if my extra added layer of insulation improved the rate of heat loss, but it worked very well for me. Plus, with the silicone sleeve I don't have to worry about dinging it up if I drop it, and I have an extremely sure grip on it.

I bought this water bottle in preparation for a trip to Disney World. To test it out, I loaded it with ice an then filled it with water. I then checked on the ice every few hours. After 28 hours, there was still a small amount of ice floating in the water.Next I reloaded the bottle with ice and then filled it with room temperature tap water. I then shook the bottle vigorously to cool the water, and then dumped the water out, leaving the ice. I then refilled the bottle with water a second time, shook the bottle vigorously to cool the water, and then dumped the water out. I then refilled the bottle with water a third time, shook the bottle vigorously to cool the water, and then dumped the water out.I was able to fill the bottle and cool down the water three times with one load of ice. I had the same results while at Disney World, all day in the hot sun. I could make three full bottles of cold water by filling the bottle with ice once. Then I just asked for more ice and repeated the process.FYI: I also purchased a "Klean Kanteen 3.0 Sport Cap" for this bottle and it fit this bottle perfectly and was completely water tight.This bottle is worth every penny I paid, and more. I now plan to get one of the larger versions to take with me out on my boat for fishing excursions.

We have tried so many different types of water bottles and were not happy. The water would either leak or overflow while drinking. The spouts or straws would be really difficult to wash even though they are dishwasher safe. We settled for basic rubbermaid bottles until we found the Hydro Flask. It is very easy to use and keeps water cool (haven't tried hot stuff yet) for a full day. Its super easy to clean. I personally don't like the noise the flask makes when the lid is screwed and unscrewed. But that's just me and not the product. It seems overpriced for a water bottle but this product acts as much more than that. It can used for storing milk or coffee too. Although its not dishwasher safe, cleaning is also super easy because we can use baking soda or distilled vinegar, something most homes already have, to get rid of the icky coffee smells that flasks tend to have.