No matter what the chemists come up with, it's impossible to improve upon good old-fashioned down for lightweight insulation. So we packed the Cosmo with 550 Fill-Power down and concentrated the technology around it. Our custom Megarex 15,000mm shell offers improved waterproofing, along with a Hextropolis embossing for a unique take on down's traditional look. YKK T5 zippers and sealed seams increase the Cosmo's weatherproofing without bogging it down with unnecessary weight. Consider this the Puffy 2.0.