mirra base layer top. the mirra top women's thermal base layer is made of a highly breathable material composed of microscopic fibers, quickly removes moisture, is quick-drying and highly breathable. the specialty is the content of silver nanoparticles, which reduce odor. pleasant flat seams are a matter of course. mirra top is made from 92 % polyester and thanks to 8 % elastane is flexible and will not restrict your movement.