FullRange - FullRange Insulation is a multi-denier synthetic fill insulation made from several different types of polyester fibers, developed by Toray Mills in Japan. It's built in much the same way as traditional fill insulation, but has a proprietary element that gives it added stability against fiber migration, and allows for great stretch and recovery. Utilizing a blend of hydrophobic fibers that repel moisture, FullRange insulation will maintain its warmth and loft when wet, and dries fast. The incredible breathability of FullRange insulation (40 CFM) means you can go hard all day with zero swamp factor and spend less time messing with layers.