A cold weather, high altitude double boot for extreme conditions The Olympus Mons is the perfect choice for 8000-meter peaks. This super lightweight double boot has a PE thermal insulating inner boot that is coupled with a thermo-reflective outer boot with an integrated gaiter. We used a super insulating lightweight PE outsole to keep the weight down and the TPU midsole is excellent for crampon compatibility and stability on steep terrain. WEIGHT: 39.86 oz • 1130 g LAST: Olympus Mons CONSTRUCTION: Inner: Slip lasted Outer: Board Lasted OUTER BOOT: Cordura® upper lined with dual-density PE micro-cellular thermal insulating closed cell foam and thermo-reflective aluminium facing/ Insulated removable footbed/ Vibram® rubber rand  See more here.