It appears to be a nice functional design but mine leaked in my pack. I discovered the O-gasket seal in the cap moves out of position when tightened. I thought it was an isolated case but when the second flask did the same thing, I replaced it with a 16oz Nalgene HDPE narrow mouth screw top bottle & the problem went away.

I have heard people say they sometimes leaked,so I tried something different then the rest,and it always works. this is what I do -don't tighten the cap a lot,cause if you do,sometimes those O-gaskets can Buckle on any lid,so I turn mine upside down and let it sit on its Lid on a paper towel to see if it leaks and if it does I just tighten it a little bit more,that's it.

worked great, purchased this one instead of the 12 oz nalgene for the simple purpose of having 8 more ounces. No leaks and would buy again.

Used this on a few camping trips and social gatherings. The wide mouth makes it easy to drink and the shot glass is a great size. It is virtually indestructible and has taken many falls. The seal is very good and I never lose any precious cargo that is stored inside of it.

One of my bird ski bros had one of these filled with Toro bravo(tequila and Kahlua) didn't seem to leak and the top was easy to take off with gloves on with the big ridges on it. the black plastic coating made it easy to hold on to as well while taking swigs on the the chair.