This flask works with hot or cold. I have used it for a few months now and have tried to make sure thwt it works well. I love that you can machine wash the pieces and they separate well to be sure the seals and insides get clean. This is always a weakness in bottles because mold can grow and this design is wonderful so mold doesn't grow. The bottle opening itself is wide that you can get a long sponge or cleaning tool in the container.It keeps drinks hot for over 12 hours so far. My longest was 14 hours before the beverage was done. It also keeps beverages cold for over 10 hours. That was also the longest the beverage has lasted with me.I would highly recommend this flask because of the durability. The handle makes it easy to carry and contain. The seals are ... MoreThis flask works with hot or cold. I have used it for a few months now and have tried to make sure thwt it works well. I love that you can machine wash the pieces and they separate well to be sure the seals and insides get clean. This is always a weakness in bottles because mold can grow and this design is wonderful so mold doesn't grow. The bottle opening itself is wide that you can get a long sponge or cleaning tool in the container.It keeps drinks hot for over 12 hours so far. My longest was 14 hours before the beverage was done. It also keeps beverages cold for over 10 hours. That was also the longest the beverage has lasted with me.I would highly recommend this flask because of the durability. The handle makes it easy to carry and contain. The seals are wonderful and it is nice to have. I highly recommend this product.

This Flask does a great job at keeping my coffee warm for four to six hours, at least in the house. I have not yet used it outdoors in cold weather. The lid, however, seems to be more complicated than necessary. I'm finally getting the hang of how to assemble and disassemble it. Don't lose the instructions for the lid. You'll need them. The lid does seem to do a good job of holding in the heat. I have not yet used this flask with cold liquids.

I received the Hydro Flask with Flex Sip Lid and I’m so glad I chose the 12 oz. instead of a bigger size. When I first saw it, I was like no way this is 12 oz. it’s too small, so I measured out 12 oz. of water and sure enough, the whole thing fit in the flask. I own a product similar to this but it’s much bigger and am not able to use it because of how heavy it is, but the Hydro Flask is perfect for me, I’m able to pick it up with no problems (I have arthritis and nerve damage in my hands). The look of the flask is cute, small, and sleek. I love the color which is like a turquoise blue color. It keeps my water cold for several hours and never has condensation on the outside due to the great insulation.The Hydro Flask is double insulated, has a wide mouth, is ... MoreI received the Hydro Flask with Flex Sip Lid and I’m so glad I chose the 12 oz. instead of a bigger size. When I first saw it, I was like no way this is 12 oz. it’s too small, so I measured out 12 oz. of water and sure enough, the whole thing fit in the flask. I own a product similar to this but it’s much bigger and am not able to use it because of how heavy it is, but the Hydro Flask is perfect for me, I’m able to pick it up with no problems (I have arthritis and nerve damage in my hands). The look of the flask is cute, small, and sleek. I love the color which is like a turquoise blue color. It keeps my water cold for several hours and never has condensation on the outside due to the great insulation.The Hydro Flask is double insulated, has a wide mouth, is leak-proof, has a handle strap, and comes with a great warranty. I love everything about this flask.I highly recommend the Hydro Flask with Flex Sip Lid. I am looking forward to getting a few more in different colors.