As a sleek micro-belay parka on chilly rock routes or as an insulated jacket during alpine squalls, the Nano Puff® traps your heat and blocks the wind. The recycled polyester shell sheds moisture and fits effortlessly in your layering system, while the low-bulk, hydrophobic, highly compressible 60-g PrimaLoft® Gold Insulation Eco warms with remarkable efficiency, even when wet.