The Nibba Fleece Merino vests perform best in cool and cold conditions, especially in activities where only light support is needed. - Slim fit design - Outer material: 100% extra fine merino wool, fiber thickness only 17.5 microns - Lining: over 90% merino wool blended with synthetic fiber - Elastic band covered with a soft merino wool layer - Sportsback construction - Machine washable at 40ºCfollow the care instructions on the package 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.