The defeet un d shurt long sleeved base layer features a unique polarity of acrylics that draws moisture away rapidly made with microsupreme acrylic fibre this base layer is incredibly soft and comfortable to the skin the defeet un d is slightly thicker than the un d lite but still very thin it works well for layering even in warm climates in cooler temperatures just layer on another un d shurt or an un d flector works wonders for cycling running and w