Layering clothes beneath an outer shell that is as waterproof and windproof as possible is critical, he says. "Layering helps maintain body heat and prevents the retention of perspiration on the skin." Closest to the skin should be a thin layer of synthetic microfibers, such as polypropylene or Capilene to help wick sweat away from the body. The second layer provides insulation. It should assist in wicking moisture as well. Laskowski suggests lightweight synthetic fleece for the second layer. He recommends polypro socks and gloves under outer gloves to wick moisture from feet and hands. It is necessary to cover exposed areas. The body loses considerable heat when the head is exposed. A hat of synthetic fleece is a good choice. Outdoor gear retailers such as Patagonia, North Face, Early Winters and Nike all provide garments which meet Laskowski's requirements for efficient layering.