Hocosa Organic Wool-Silk Undershirt for Women Made of 70/30% blend of soothingly soft European KbT- certified organic merino wool & silk. Wool for warmth. Silk for strength. Light-weight. Natural fibers breathe, maintaining a comfortable temperature in warmth or cold. Wicks moisture away from skin, keeping your dry & comfortable. Even when wet, feels warm. Natural wool with lanolin gives self-cleansing properties for easy care. Can go weeks without washing & still remain fresh. Wash occasionally, by hand with lanolin-containing wool-wash for best results.