For winter or altitude you will want heavy-weight top and bottom underwear, a fleece or down jacket, and a long shell. 2 Down jacket or vest Traditional layering piece. The down vest at right supercompacts to the size of two medium fists and makes a supergreat pillow. Gloves Fast-drying materials like pile and polypropylene are preferable as wet gloves are no fun. If it's really cold you will also need a pile, acrylic, or wool cap.
Socks Are crucial travel equipment.
I recommend the Thorlo or equivalent brand of hiking, walking, and sports socks. These have thick padding at the heel, ball, and toe areas, and are made of acrylic or Coolmax, which wick moisture away from feet and dry quickly. Cotton socks wick poorly and take a long time to dry, resulting in blisters. Liner socks Some backpackers swear by these for preventing blisters. Liners socks are very thin and worn under regular socks.