I got the medium to go over a small first lite wick however it is too loose for me even as a midlayer. I was unable to exchange it because I accidently ripped the tag off during the try on process. It is a brand new kiln in the new Cerca Pattern. It has only been worn once, which was me trying it on. The Kiln Midweight 250 Merino-X fabric utilizes ultrafine, 18.5 micron merino wool in a high loft, interlock knit to create styles that surpass expectations in the broadest range of temperature and weather conditions. Blending a small component of spandex into this knit, these lofted interlock pieces can withstand extended hunts in the field, regardless of the season.