How warm is a cashmere windbreaker?

‌Cashmere windbreakers are very warm, and their warmth retention effect is better than that of wool windbreakers. ‌Cashmere is a natural fiber extracted from goats. Its fibers are fine and hollow inside, which can store a lot of still air and form a layer of "air insulation layer" to effectively prevent heat loss. The warmth retention of cashmere is 50%-8 times that of wool, which makes cashmere windbreakers more warm at the same thickness.