Best sleeping layerWhat you change into at the lodge and sleep in
Smartwool Classic Thermal Merino Base Layer Bottom
The single best sleep-warmth upgrade above 4,000 m and it doubles under trousers on a cold pass; at 250-weight it is too warm to walk in on any ordinary day.
Skip it ifLow-altitude treks. Below 3,000 m you will never take them out of the bag.


