Regular down takes on water and is very difficult to dry; DriDown proprietary process treats each individual duck down plume with a hydrophobic finishWith the duck down now resistant to water, the insulation maintains its loft and stays dry 7 times longer than untreated downIt also performs better in high humidity than regular down and, in case it accidentally gets wet, it will dry out faster, tooLightweight yet durable 30-denier micro-ripstop polyester shell and comfortable, moisture-wicking polyester lining warm up fastBaffle construction keeps down from migrating, eliminating cold spotsFull-length 2-way, double sliding zipper allows easy venting; locking slider is backed by wide, antisnag binding tapeSnag-free zipper tracks prevent the dreaded stuck zipper by creating a barrier between the lining and the zipper trackFully insulated draft tube backing the zipper keeps body heat in and cold air outErgonomic, nonrestrictive hood cradles your head in warmth; hood features differentiated drawcords that make fit adjustments easy, even in the darkRoomy, ergonomically shaped footbox enhances comfort and warmth of feetSierra Designs Zissou 23°F comes with stuff sack and storage bagEuropean Norm (EN) is an independent third-party temperature rating, allowing accurate comparisons across brands with other EN-rated bagsImported.