If butter were a fabric, this would be that fabric. The benefit of Light Lux, vs. Classic or Heavyweight, is its readiness for rising temps. It's ultra soft, like all Lux, but the light version also makes it perfect for a warming season, when body heat ramps up quickly. Its softness also makes it a favorite for how it feels on your skin. We've been loving this long sleeve as a single layer for runs, but also as a baselayer under mid- and outer-layers. The fit is classic, with ample room in the arms and torso. Not clingy, not blousy, just right.