This is a Ivory women's limited-edition Tracksmith® X J.Crew Downeaster quarter-zip sweater in size M. It's 60% merino wool/40% polypropylene, super comfy. Run's a bit big for me. Never worn, new with tag. The Downeaster features a double knit blend of 60% Merino wool and 40% polypropylene. The natural properties of Merino offer warmth, breath-ability and odor-resistance, while polypropylene improves wicking and insulation. Not only does polypropylene have the lowest thermal conductivity of any fiber, which means it holds onto heat the longest, it’s also hydrophobic, quickly pulling moisture (i.e. sweat) to the surface where it can evaporate, rather than be absorbed into the Merino. The end result is a high-performance mid-layer that doesn't scream 'technical.'