Does Not Leak, I don't care what you do to it. If you fill it with ice, there will still be ice in there 72 hours later, I'm not joking. And if you haven't opened it, it will have barely melted. If you fill it with a boiling hot beverage, it will still burn you hours and hours later when you first open it. So be careful lol! I deliver packages 12 hours a day for a living, and so this thing has been put through its paces. it's been dropped. kicked. Flew out of a P-1000 with the doors open a couple months back going about 55-60 MPH, went bouncing down the incredibly potholed country highway and eventually smacked into a concrete bunker/thing at an intersection, some kind of protection for a power box or something. Anyway this thing was whamming around so loudly I could hear it OVER the cacophony of clanging that a P-1000 creates as it moves over even the smoothest of roads, and this one is NOT smooth. It's like the polar opposite of smooth. So I was sure it was done. Like I saw it flipping and stuff in my mirror and I was instantly upset because I love the thing. But I went back and picked it up, more to keep from adding to our country's litter problem than out of any hopes of recovery. I picked it up fully expecting to get doused with the icy juice I had filled it with that morning. I was puzzled when not a drop came out. NONE. I turned it upside down. NOT A DROP. The cap is a bit difficult to unscrew now after the impacts, but it still DOES unscrew, and still doesn't leak. I've been using it since and it still keeps ice frozen for days and still doesn't leak even when filled with boiling hot tea. This thing is TOUGH. So yeah, it's not the greatest looking thing in the world it's kind of basic, but If you are looking for something that's actually going to last and do the job that it was created to do, THIS is your jug. Soda, juice, water, boiling hot tea, you can put anything in here and it's going to keep it whatever temperature you want it at virtually forever. Heat and cold do not transfer across a vacuum hardly at all, and this thing has a vacuum layer of nothingness in between the layers of metal which keeps the temperature from bleeding in our out or anywhere. Get it, you won't regret it, although it does clank loudly when drinking from it if you have ice in it so if you're like worried about, idk, rabid bears hearing you and honing in on your position from the sound then I would go for something else, but other than that I see no downsides to this jug whatsoever. 11/10 would recommend to anyone and everyone that needs to stay hydrated on the go. Of course now that I have written this review sales will increase and then the price will skyrocket and then the company will get greedy and start cutting corners to keep profits increasing from quarter to quarter and it'll be a piece of garbage by 2027 but until then BUY IT lololol.