A friend just offered to sell me his old La Sportivas. I think these are "Trango Extreme EVO Light GTX," as they have the same patterns on the syn leather, but the leather is red (not silver); they weigh 3 lbs 10 oz/pair for size 10.5. The boots are a few years old; apparently the toe box was too tight for him.

The newer "Trango Extreme EVO Light GTX" are supposedly insulated, by using "GORE TEX DURATHERM." What is that? These boots are not that thick on the sides of the foot. Is Gore Tex Duratherm some combination of a thin insulation with a PTFE vapor barrier? From the reviews, the new models don't seem like really warm boots.

Hi, I have some Scarpa Summit boots that are lined with GoreTex Duratherm. The GT Duratherm is similar to any GT waterproof lining. Its stitched on the inside of the boot. Its just thicker than the normally thin GT liners and feels like it has a different material incorporated in. It offers some insulation and it also helps that duratherm is usually used in thick leather mountaineering boots with fully gusseted tonge.

Maybe it is gore-tex with an aerogel insulation layer.

I just read this:
"Gore-Tex Duratherm is Gore-Tex membrane laminated to a light, insulating
hollow fibre. It allows breathability, waterproofness and a reinforced insulation
to respond to winter conditions. Gore-Tex Duratherm is used in the Fiamma
GTX."

http://lib.store.yahoo.net/lib/gusa/lining.pdf

Now I just have to figure out what these boots actually are, and whether they used this stuff.

Here are the boots in question. Again, I think these are "Trango Extreme EVO Light GTX," but those boots haven't been made in red for years, so I wonder if the specs are much different on the newer silver version.
http://hwstock.org/gear/boot2.jpg
http://hwstock.org/gear/boot3.jpg
And for people who won't click a bare link,

Your picture shows Trango S Evo GTX boots, which are still in production by La Sportiva. BTW The same color can be purchased from Ex. Mountain Gear Catalog today for $289.00 new, FWIW. Good boots, I have been abusing them since 05, still do. No Gore-Tex Duratherm on these, just Gore-tex barrier. These are the lightest boot in La Sportiva quiver, less warm but also less bulky then Trango EXT Evo Light GTX. They are rather specific use boots, three season alpine boots that accept new-matic crampons (g-12s work well with these) and climb rock well partly because of the POINTED TOE and partly because of good rubber. I use them in winter as well, but I rarely get cold feet.

Thanks -- I guess the lack of a crampon groove in the front should have clued me in. This fellow thought the boots were insulated (they didn't seem to be, but I thought the insulation might be very compact). They are also heavier than I expected -- 3 lbs 10 oz/pair for size 10.5. The thermal conductivity through the sole may be more important, for "summer" climbing on snow.

My normal approach shoe size is men's 9.5, and I often get size 10 in heavier boots. I was told these were size 10.5, and they seem to fit with one pair trekking socks.

Thanks again.