Your question reminded me that I need to get some pics and post a follow-up on my DIY sock made from the mystery material first posted in this thread: https://www.hammockforums.net/forum/...ad.php?t=64226
(The sock experiment starts about halfway down page-2)
I used this sock two different nights, the first in the low 30's and the second was a low of 28º. I really wish I'd had opportunity to test it during a colder night, but things just didn't work out. Both of these test nights were before I bought my little hanging thermometer, so I don't know what the temp inside the sock was, just the reported low for each night. But I can tell you, it definitely creates it's own little climate in there - both nights when I got up to water the tree, I was shocked at how cold it was when I opened the sock to get out! Also, I like the sock because it eliminates the constant cold breeze blowing across my face while sleeping.
As for condensation - I'm the odd man out, because I had ZERO condensation, frost, or even moisture inside the sock on either night.
I attribute that to the design of the material (similar to UnderArmor) because it seems to be designed to wick-away or "breathe" moisture, so it never builds up on the material.
The penalty for this stuff is weight - it's probably about the same as a canvas sock - not an UL.
I will rig this thing in the shop if I have to just to get some pics, and will report back . . .