The Tuvegga Air shirt has two sides: one is smooth, and the other has a textured surface. The smooth side against the skin enhances breathability, while the textured side provides extra warmthchoose depending on the situation. - Merino wool naturally resists odor and stays warm even when damp - 99% merino wool, 1% elastane - Fabric weight 250g/m² - Fiber thickness 18.7 microns (fine fiber) - Machine washable on wool program Devold undergarments are treated with a natural compound made to protect the apparel from wool-eating insects. It has a gentle, citronella-style scent and is completely harmless to people. The treatment protects the garment for one year and its scent diminishes and fades away with airing the garment. Take good care of your Merino apparel - regular detergents are a bit over the top for use with wool, so we recommend using [Nikwax Wool Wash](/wool-wash/), regardless of whether you wash your apparel in a machine or by hand.