Lightweight and supple, the REI Co-op Silk long-sleeve crew shirt provides great warmth for its weight and offers luxurious comfort. Features Lightweight, breathable, pure silk jersey keeps you warm and comfortable Dropped back hem stays tucked in Rib-knit finish on neck and cuffs Hand wash warm and lay flat to dry; do not bleach or iron REI is Climate Neutral Certified; as we work to actively reduce our footprint, we measure annual carbon emissions and purchase an equivalent amount of verified carbon credits NF