Taken from La Sportiva's site...
A sturdy, durable double boot for high altitude mountaineering
When the conditions are cold and high the Baruntse offers a hospitable climate to keep your feet warm and dry. Ideal for use on 6-7000 meter peaks or in harsh winter conditions where you don't want to think about your feet. The thermo-formable inner boot sports the patented speed lacing system and couples with the highly insulated multi-layered PE outerboot for dependable warmth and a PU coating to keep moisture and cold outside and heat inside the boot.
FeaturesWEIGHT: 44.7 oz/ 1267 g LAST: Nuptse CONSTRUCTION: Inner Boot: Slip Lasted Outer Boot: Board Lasted OUTER BOOT: Transparent PU Tech anti-abrasion film with high insulation expandied PE/ High density expanded PE insulating netting/ Synthetic mico-fiber/ High abrasion resistant Cordura®/ Giugiaro lacing hardware INNER BOOT: Anti-abrasion Cordura®/ Thermo-moldable 7mm high density insulating EVA INSOLE: 6 mm isulating Ibi-Thermo + PE insulating barrier and aluminum insulation MIDSOLE: 8-9 mm TPU/SBR Air Cushion SOLE: Vibram® Montagna