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.