icebreaker has the world’s best merino wool layering system. Our thermal underwear for women is made with superfine merino wool, sourced from our growers in New Zealand. Merino wool clothing is naturally breathable and wicks moisture from your skin, so you can stay feeling comfortable all day. Wear our women's base layers as thermal tops and leggings for warmth in even the most extreme cold, or under your winter clothes for cozy comfort. Merino regulates your body temperature in both heat and cold, and is naturally odor-resistant, so you can stay smelling fresh for longer. Layer with our women's tops and trousers for cool-weather outdoor adventures or training.
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icebreaker weighting system. The larger the number the warmer the garment.
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The bigger the number, the warmer you'll be.

From summer heat to winter chill, there's a fabric weight to keep you in your comfort zone.

320 - 380 Heavyweight - Built to keep out the coldest conditions.

240 - 280 Midweight - Best suited for cold conditions.

200 - 230 Lightweight - Best suited for moderate to cool conditions.

150 - 180 Ultralight - Versatile all season performance.

120 - 135 Featherweight - Best for warm to hot conditions.