Sprayway down filled garments use 80/20 Natural Duck down with 550cu.in/oz fill power (european standard). Down has great lofting properties which means that it traps small pockets of air between the fibres. The air is quickly warmed by body heat, and so gives high levels of insulation from a lightweight garment. Down garments are by nature very packable because the loft can simply be compressed out by rolling the garment up.
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