I took it off, dumped the water out and fished ice fished all afternoon. Within maybe 20min my foot was warm again.... no kidding.
I stepped in a hole some what had made a little to large and did the same thing, kept fishing.
There is something like 26 layers of felt with air bladders in between the felt, it works.
They are very few things I hunt/ fish with that I have been as happy with as these boots.
I posted this picture the other day on another forum, it was -28 far I wasn't in a ice tent or shante all day my feet never got cold.
Three out of the four pictured and the guy taking the photo all had the boots on.