Throw Blanket Nylon/Down FillAside from its soft luxurious feel and excellent insulating properties, the 23 Zero Down Trail blanket breathes naturally, absorbing and drawing moisture and perspiration away from your body and preventing a clammy and uncomfortable sleep. No man made fiber can replicate the warmth to weight ratio of a well designed down comforter. Insulated with 80% responsibly sourced duck down Cassette style boxed construction maintains even distribution of warmth