Nylon shell over upper chest and shoulders has a durable water repellent (DWR) finish that blocks wind and sheds light rain Light stretch insulation provides light technical warmth built for movement Fleece-backed stretch polyester across back and under arms provides high level of mobility Large, fleece-backed zippered hand pockets and sleeve pocket securely store essentials Full-length zipper provides ventilation to cool you down Reflective details on front and back aid in visibility Thumbholes hold sleeves in place while running; fold-over hand cuffs offer extra warmth Contains materials that meet the bluesign® criteria REI Co-op brand is certified to The Climate Label; we actively fund efforts to reduce carbon emissions across our business and support climate projects around the world Fabric Chest, shoulders and upper back: ripstop nylon (bluesign®-approved); lower back, forearms, underarms and lower torso: 91% polyester/9% spandex grid-back fleece (bluesign®-approved)