Light yet durable 100% nylon ripstop shell and plain-weave lining offer generous mechanical stretch and exceptional breathability, with a DWR (durable water repellent) finish Revolutionary 40-g FullRange® insulation warms and stretches; combined with the shell and lining, this creates excellent mechanical stretch and unprecedented air permeability (40CFM on front; 130CFM on back) Airy, wicking waffle knit on the backs of arms and side and back panels manages excess heat and moisture Stretchy hood with binding easily pulls on or off, even when jacket is zipped Two welted, zippered handwarmer pockets are low-bulk to wear comfortably with a harness or pack Sleek, low-bulk, snag-resistant cuffs use stretch knit with discreet thumb slots to provide versatile coverage and comfort Stretch binding at hem to seal in warmth